From Team Fortress Wiki
Looks like that there just weren't the place you oughta be standin'!
— The Engineer
The Legend of Bugfoot is a miscellaneous item for the Engineer. It is a pair of insect-like feet that replace the Engineer's normal boots.
This item can only be worn around Halloween or during a Full Moon; at other times of the year, it does not appear in gameplay, unless the server has Halloween mode enabled. However, it can be equipped at any time and can still be viewed on the loadout screen even when it is not visible during games.
Engineer's vocalizations are 145% higher pitch.
October 27, 2011 Patch (Very Scary Halloween Special)
- The Legend of Bugfoot was added to the game.
- The item name is a pun on the legend of Bigfoot, a myth about a large ape-like humanoid that inhabits forests.