Allright. We all hate Tech-Priest. Everyone does, it's only natural. Now, how to really ruin their day? When they reach Rank 8, have nasty Dragonscale Armour, Rosariuses and Amulets of Warding and a Tougness that lets them survive meltabombs stuck to their asses. They Maglev their way out of lethal drops, Laugh at Fatigue and unleash veritable hordes of combat servitors and skulls at anyone you send their way.
Let's have it! Electromagnets in the walls, EMP bombs in the mail, I'm all ears