So if a certain number of people show up to a mark, say 50 for a B and 100 for an A, upon death an "Avenger" spawns and immediately blankets the area with powerful AoEs. And it doesn't despawn after that; it just keeps roaming the area looking for more players to kill, requiring some truly 1337 endgame raiders to come in and clean up. Only two mercies: it stays out of sanctuaries, and it's HP doesn't recover between pulls.

Never gonna happen, of course - Yoshi won't do anything to damage the game's accessibility - but it's nice to dream.