Spy disguised as Pyro TF2
"He could be in this very room! He could be you! He could be me! He could even be- (shot by BLU Soldier)"
The BLU Spy speaking about RED Spy, shortly before, well...

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.

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