Besides playing with Pyromaniac in Blood Ties (someone miscasted Shriveling, creating a fire in the caves; uh-oh!), mine is from Season of the Witch. I was playing against one of my friends while he controlled two investigators. Keziah Mason appeared and I commanded her from one end of the map to the other side. Seeing as the objective was to kill her, my buddy chased after her, puzzled by my tactic. She reached the locked Ceremony Room. Next turn, one of his investigators opens the lock to be killed instantly! The door is trapped with Alien Gate, which appears in whatever room Clue 1 does not appear in. She will start in either the Ceremony Room or Cave 1. Racing her to the other room she did not appear in creates a lethal boundary, and is a hilarious way to solidify a win as Keeper. My friend and I were rolling from laughter after the fact.

But only one investigator was killed! Why didn't the others investigators kill the witch?

You will have to play to find out.

My favourite moment is also from Season of the Witch. There was a Shoggoth in the garden, and when a player shot at it they hit a lantern and set the garden on fire. So the Shoggoth went to hide in the shed, along with the portal. Meaning that the players had to go through a garden on fire and then risk sharing the shed with the Shoggoth or stand outside getting burned. Especially because it was an accident caused by the combat cards it provided a lot of laughs.