From Team Fortress Wiki
The Spy has the unique ability to disguise as other classes, both on his own team and the enemies. This, as well as his cloaking ability, helps him move unnoticed among the other players. While wearing a disguise, the Spy will appear as the disguised class from the other team's perspective, and to the Spy's teammates, he appears as a friendly Spy wearing a mask representing his current disguise.
Applying a disguise
On the console version, a disguise can be applied by opening the Disguise Kit, selecting the desired class to disguise as, and pressing confirm. (default: - Xbox 360) On the PC, a disguise is selected by pressing the number corresponding to the class the player wishes to disguise as. For example, a player could press the key to disguise as an enemy Heavy.
Alternatively, a PC player may use the 'Simplified Disguise Menu' from the advanced PC Options. When using the Simplified Disguise Menu, a player first presses, , or to select a class category (Offense, Defense, or Support) and then presses , , or to select a class from the group. For example, a player might press to select Offense, and then press to select the Pyro as their disguise.
By default, the player will disguise as a member of the opposite team, but they may also choose to disguise as one of their teammates by pressing the 'toggle disguise team' key (default: on Xbox 360) while in the Disguise Menu. A disguise may be selected as normal afterwards, and pressing the toggle key again will switch back to enemy disguises. On PC, a player may save themselves time by pressing the 'last disguise' key (default ) which will automatically disguise as the last class and team the player selected from the Disguise Menu.on PC,
Using the Disguise Kit is not instantaneous. After a disguise is selected, a Spy will produce glowing particles of his team's color and a brief cloud of smoke for approximately two seconds, after which he will stop emitting these particles and be fully disguised as the selected class and team. This can be avoided by being cloaked to any degree before selecting a disguise; once a disguise is selected, smoke particles begin forming which will not be hidden by cloaking; however, selecting a disguise while already cloaked will produce no smoke or team-colored particles. In either case, disguising creates a small amount of noise, which is somewhat dependent on which cloaking watch is used; these sounds can potentially give away the location of a Spy.
If the player has Your Eternal Reward equipped in their Loadout, the Disguise Kit will be disabled. The Spy's only means of Disguise requires him to perform a successful Backstab on an enemy team member; non-backstab knife kills and kills with other weapons will not trigger this automatic disguise. Once successful, the enemy dies from the backstab, and the Spy will immediately assume a disguise identical to the enemy they just killed.
Gameplay while disguised
While disguised, the Spy's team will see him wearing a paper cut-out mask bearing the face of the class he is disguised as, and when they aim at him, his health indicator will display the team and class he is disguised as below his name (e.g. "Disguised as enemy Demoman" or "Disguised as friendly Sniper"). Enemies on the other hand, will see him as the team and class he is disguised as, and when they aim at him, he will appear to have the identity of an allied or enemy player with his disguise. If the chosen team has at least one player of the chosen class the Spy disguised as, the Spy will take on the identity of one of those players randomly. If the selected team has no player of the selected class, the Spy will take on the identity of any random player on the selected team regardless of class. When a Spy copies a player's identity, he takes on the name, health, and weapon load-outs of that player unless the Spy disguises as a class that the chosen team has no players of. In that case, the Spy will have the standard loadout. If the chosen disguise class has a slower move speed than the Spy's, the Spy will reduce his speed to match that of his disguised class's default speed except when cloaked. Loadout effects that change the speed of the class, such as the Scotsman's Skullcutter are not taken into account nor will his speed increase to match that of the Medic or Scout if disguised as either.
When disguised as the enemy, Spies do not bleed from enemy fire nor do they receive knockback from any source except the Pyro's Compression blast and the Scout's Force-A-Nature. Weapons with "On hit" effects such as the Blutsauger do not trigger when hitting, including hits that kill the Spy. However, Burning, Jarate and Mad Milk will affect disguised Spies as normal. Weapons that positively affect allies on hit such as the Disciplinary Action and the Crusader's Crossbow will not grant these to disguised enemy Spies and will damage them as normal.
While disguised, a Spy can pick up Health kits to recover the 'health' of his disguise in addition to his actual health, if the player he disguised as was below full health at the time he disguised. This false health recovery will still work, even if the Spy's actual health is full. Inversely, a Spy who is injured, but their disguise's health is full or Overhealed may still pick up a Health Kit. However, the cross icons that appears above him while healing will be his actual team's color, not the color of his disguise.
Actions while disguised
While a Spy is disguised as an opponent, he cannot capture a control point, push the Payload nor block the enemy from doing the same. However, a Spy disguised as a member of his own team may continue contributing to capturing a point or pushing the cart as normal. However, enemy Buildings will still treat him as normal, and enemy Medics will not be able to heal him. The effect of a friendly disguise is limited to simply causing him to appear as another class to players on the enemy team.
Inversely, a Spy using an enemy disguise will not be targeted by Sentry Guns, can use enemy Dispensers, and can be healed by enemy Medics as though he were a member of that team. Teleporters are the only building that work exactly the same for both disguised and undisguised Spies.
Also, there are several actions that can be taken that are specifically designed to make the disguise more convincing to enemy team members:
- Changing disguise weapon - Changing to the primary, secondary, or melee weapon and pressing the 'last disguise' key (default Scout lets you appear to equip the Bat). If the person you are disguised as has equipped an unlockable weapon in the chosen slot, you will appear to be wielding the same weapon in your disguised state. ) will cause the disguise to mimic the weapon of the class in the same inventory slot. (ex: holding the Knife while disguised as a
- Reloading - If your disguise weapon is one that reloads a magazine or shells (e.g., Shotgun, Rocket Launcher, Scattergun, SMG, etc.), reloading your Revolver (default ) will cause your disguise to reload their weapon. This does not apply to weapons like the Flare Gun or Sniper Rifle which do not have magazines as such. You cannot fake a reload while your Revolver has all 6 rounds loaded, or while disguised with a weapons like the Minigun, which have no reload animations. Reloading will play the Revolver sound clip, regardless of the weapon being reloaded.
- Voice commands - Any voice commands made while disguised will broadcast to your team as coming from you and to the enemy team as coming from the person you are disguised as. You can call for an enemy Medic to heal you in this way. This can, however, alert the person you are disguised as to your presence since they will see voice commands attributed to them but not coming from them, and they may tell their team.
A Spy will automatically lose his disguise if he is killed, steals the enemy's Intelligence, or if he attacks with any weapon apart from the Sapper. Alternatively, a Spy can manually remove his disguise by opening the Disguise Menu and selecting a Spy on his own team.
- Disguises do not change your actual hitbox sizes, shapes, or positions. Using certain disguises can therefore reduce the risk of Headshot.
- If you pick up health kits or get healed, your disguise will appear to gain health accordingly. This allows you to pick up Health Kits even if your health is full so long as your disguise's health is not.
- You cannot taunt while disguised.
- You gain knockback immunity, regardless of disguise color, with some exceptions (such as the Pyro's compression blast).
- Disguising does not change the fact that Spies can walk through teammates but not enemies.
- The Sapper will not remove the disguise if used.
- Certain classes that have weapons that cannot be actively used, but instead are worn (such as the Razorback, Darwin's Danger Shield, or the Gunboats) can allow a disguised Spy to appear to have both the default weapon and the wearable item equipped simultaneously, creating an impossible loadout and potentially giving away the Spy's disguise to observant players.
On the PC, the Disguise function can also be accessed directly through the Developer's Console using the 'disguise X Y' command with the following parameters:
|Class||X Value||Team||Y Value|
- It is possible for a disguised Spy to have the appearance of equipping two weapons that share the same slot. In the example above to the right, the Spy disguised as a Sniper is holding the Darwin's Danger Shield and the Submachine Gun, both secondary slot weapons.
- A Spy disguised as a player with weapons that grant passive effects (such as the Scotsman's Skullcutter) will not possess these passive effects (e.g. decreased movement speed ).
- If a Spy tries disguising as a player with the Huntsman or Machina, they will appear with the stock Sniper Rifle.
- Disguising as a class that the enemy team does not have may cause the disguise's displayed health to be an impossible value. For example, if the enemy team has no Scouts, and the Scout disguise decides to choose a Heavy player's name, the Scout disguise will also take on the health of the Heavy (such as 300), which is an impossible value for a Scout to have.
- A Spy disguised as a player of the enemy team may incorrectly display his actual alias to his opponents when aimed at or through the use of voice commands.
- If a Spy disguises as a Soldier, Pyro or Heavy when no one on either team is playing that class and the Spy changes his disguise weapon to a Shotgun, he will be disguised as a civilian of that class. Doing the same thing for an Engineer yields a different effect, where the Engineer holds whatever the Spy's active weapon is. 
- If a Spy disguises as an enemy Soldier who has the Battle Bob equipped with the "Without Helmet" style, the disguise will have a helmet on.
- When spectating a disguised Spy, the "X is currently holding" box may display weapons and items that actually belong to the player the Spy is disguised as.
- If a Spy is disguised as a member of his team and uses voice commands, the enemy is notified of these commands in chat as enemy voice commands.