Okay I have a true loving story that is too good to pass up. Best told in green text form.
>Fallout 3 Broken Steel
>Destroy Enclave's mobile platform mission
>At one point in the mission, there was a mind-controlled Deathclaw that aided me inside the platform.
>I beat the mission and haven't seen the Deathclaw since.
>I get thanked at the Citadel or whatever.
>Fast travel to Megaton
>same loving Deathclaw (It had the mind control equipment on) attacks and kills the sheriff
>The Deathclaw has green health (ergo, not an enemy) and it's killing civilians
>I kill the Deathclaw and it's body goes so high up in the V.A.T.S view that it surpasses the skybox
>I was in literal awe for 30 seconds, not exaggerating
>That wasn't the weirdest thing as I had yet to learn
>I go into the bar in Megaton, same loving Deathclaw spawns a few seconds later
>Panic because it's killing everyone inside
>Shoot like a motherforgeter
>Accidentally kill an innocent
>Megaton now hates me
>Go out of the bar
>Megaton citizens shooting me
>Dead Deathclaw lives once more and kills everyone in sight
>It never harms me
>Literally everywhere I go, there is death
TL;DR: A glitch occurred where a Mind-controlled Deathclaw spawns everytime I go somewhere new and it kills everyone but me.