>>532664529
MECs in Enemy Within, where you chop off someone's limbs so that they can pilot a mech suit loaded with heavy guns and can cast fist. Ayy lmaos later field their own sectoid versions that are lame because they lack the fisting power.
2 had SPARKs which are just robots and a bit underwhelming without mods. Fucking great when you throw in a buncha mods though, Titanfall related ones being essential. Can still fist enemies but IIRC don't get any special finishers like MECs did.