They are very inhuman and barely able to be alive, here are some examples:
Spoiler!
If you want some specific features for your cripples, (gender, extra broken arms, extra antennas, tell me) Even made 1 comic:
http://imgur.com/FRLUu,hsTgF,eAAf4,J1BfX,4SuVv - Son of Evil Dad, part 1.