What happened when general custer took off his boots worksheet?

He felt the defeat.

General George Armstrong Custer is a famous army leader who was overpowered at the "Battle of the Little Bighorn" fought in 1876, amid the "Indian Wars", when battling against the indigenous people.

The "joke" depends upon the homophonous comparability of "defeat" and "the feet", along these lines when removed his boots he experienced the feet.