Running Corpse Bug

I know the bug has no real useful applications, but it's still a hilarious bug in Vanilla Doom that makes you go "What the...!" when you first see it.

Let's say there's a deathmatch going, and in the map, all deathmatch player starts are considered "blocked" (They may not actually be blocked, but the engine thinks they are), and Player X dies. When Player X tries to respawn, the engine determines that all deathmatch starts are blocked, so it falls back to the regular Player X coop start spot. But if there is no Player X coop start, the game doesn't fully respawn Player X, but it assumes he respawned.

The result? Player X is now a corpse, moving around the level. He can't use any weapons, respawn, or pick up any weapons. Other players will see him as a corpse sliding about.

I was messing around with a level that purposely invokes this bug and I actually made an interesting discovery in Chocolate Doom. Running corpses count as monsters! What first caught my eye is that they cannot go through monster blocking lines. Upon further inspection, they have quite a few of the properties of monsters. They cannot close opening doors, they can go through monster-only teleporters. DeHackEd-willing, they can even be resurrected by Archviles!

Has there been any other information on this since Toke and his friend discovered it way back?

All of these effects would be caused by the mobj_t's player pointer being NULL. That's what is is used in a significant number of cases to distinguish player objects from other objects.