Chopa is a hindi word used to jeer, ridicule or make fun of an individual, group or even events which failed miserably in doing whatever they claimed they would.
Bhai jyada hosiyar banraha tha, iska chopa ho gaya
A person pretending to be something they aren't, or an impostor. This is inferred because of the old alien movies where alien pods appear on earth and the "pod people" dispose of the humans and slowly reproduce the bodies, pretending to be humans.
The pod person was pretending to be my father, but I knew that he was an alien when he acted differently than my father ever would have.