"Defeat ?1!?" is an objective in the sidequest Victims of Vault Hunters in Sir Hammerlock vs. The Son of Crawmerax.
Walkthrough[edit]
Head over to the Wooden Mask by the fireplace.
Interact with it to reveal a hidden passage beneath the fireplace. Follow it through and look to the left. You will see ?1!? impaled on a number of spikes.
Dialogue[edit]
Sparky Flynt: So yeah, I got no idea what's going on with this last guy. I think he wants Zero dead, but I didn't really understand anything he said.
Sparky Flynt: Surprising NO ONE, he's dead too. I swaer. I'm gonna figure out who did this. Whatever, I'm done getting chumps to do my dirty work. You find me, and I'll kill you myself for you did to my dad!