Yeah it was the I.R.A. (Infinitely Regenerative Automaton) an Anniversary/Living Legends raid around the time of Secrets of Faydwer (during the same time they revamped Blackburrow/Lower Guk to be level 75-80 which incidentally i think would also be rather cool
*hinthint*) You got different levels of augs or each wave you killed. You killed the same giant Steamwork mob over and over until you wiped and it got harder each time. They did it a couple times i believe.