Someone who is an utter twat. Stupid beyond belief.
This orignates from the GCSE course DiDA which pupils absolutely hate. Therefore, the insult DiDA was made to compare the person described as the most tedious and boring ICT course in the world.
Molly, Zoey, Charlotte, Shauna you guys are such a DiDAs.
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.