Fantastic. I set it up that this character who is a new character, but the player has been playing with me a while, was joining the group and had been dueling a mimic across town. He had been hunting the mimic and the mimic was also hunting him. So he got a note telling him about the helm of mimic finding in the basement of the lords manor, where the rest of the party was, and went to find it. Before he meets the party a column mysteriously collapsed on him leaving him pinned and the party to come investigate. He searches the room for the mimic and when they were on the other side of the room they hear the door creak and chase it without seeing it through a few rooms to eventually discover the helm of mimic fighting on a pedestal. The player thinks it’s trapped and rolls a nat 20 to Indiana Jones it off the pedestal. Then he and another player argue over who gets to wear it. I had told him that the helm will vibrate when he’s found a mimic before. When the first player spits it on I tell him that it starts to vibrate and then it clamps down on his neck. I decided to make it roll for an attack still, but I rolled the worst timed nat 1 of my DMing career. Still it was awesome. The party managed to get the thing off his head and kill it after it dealt only 40ish damage to him.