This mob is not entirely known about and actually doesn't have a base mod where it originates from. The Glitch of Death is almost sentient in the ways it can harm you making players believe their game is "haunted".
Users say they experienced many strange happenings in their world from random mobs spawning in their homes, blocks getting destroyed, experience drainage, shrines placed, note blocks making sounds, etc. Also this mob uses many "entities" from other mods like lit TNT, spells, and paintings. If on multiplayer, players say sometimes the Glitch of Death turns into an overpowered version of another player and says you were killed by the player if killed by it.
The only way to kill it is to kill three random Death mobs it spawns and the Glitch ends.
How to Spot It
Getting this almost curse-like annoyance in your game is only about a 2% chance so fortunately finding draconium in the over world is more common than this mob. If you do see peculiar things in your home then there are many ways you could spot this mob early on. It is better to know of this mob early on as its powers get stronger and when it does get stronger its effects may range from random diamonds to mobs in your home regardless of light level. The easiest way to see the Glitch of Death is to light it on fire (as for some reason it uses a base player form for its model so fire effects stay the same and many items look like their on an invisible player when being held by it) or seeing the Glitch as a red mist that drains hearts. You may also hear potions being drank which is what it most commonly sounds like when the Glitch is coming.