In all my years of gaming I've never understood boasting about being a "killer DM."This guy (played briefly in college with him) claimed he was a very old school DM. One of his favorite tricks was to cripple a PC if they got too powerful. And by powerful, it usually meant they could stand up to his amazing NPCs who were supposed to be awesome and powerful. He targeted spellbooks, forced alignment/code conflicts that would cause divine characters to lose their powers, and if you got a too awesome set of magic items, you better be sure he was busting out Disjunction, Crystal brittle, or other item destruction. He also would lock you in dungeons with vampires to de-level you if you got too powerful. There is a good reason I have negative reactions to a lot of those "old school killer DM" boasts
It's extraordinarily easy to kill PCs or to take their stuff, make them depowered etc. As the saying goes the DM has infinite dragons.
Anyone who thinks that's, in any way, the mark of a good DM, is not someone I want to be playing with.