All these years later and Pigcops still have an annoying habit of dropping to the prone position and blowing my balls away.

Bastards.

What's a G.L.O.P.P.?

Nickbond12 is referring to Manhattan Project.
http://dukenukem.wikia.com/wiki/G.L.O.P.P

whereas I believe that zomgieee is referring to Duke Nukem 3D where the Pig Cops do indeed drop to the floor to avoid your shots whilst simultaneously taking shots at you.

Ah, alright.

I also remember them ducking in Duke3d. Not sure if that's what make them hard to fight against, or if it's not just because they have shotguns rather than weedy laser pistols.

In any case, I greatly enjoy blowing THEIR goddamn motherfucking pig-balls off!

(Never played Manhattan Project.)

Eh, with the shotgun the ducking pigcop has a smaller hitbox, so you'll miss with some of the spread. The ripper has no trouble with pigcops.