Heist used to own a massive satchel. In this satchel he placed every item he owned that could conceivably be made into something that could conceivably be made to explode. Interestingly-coloured sand, old cartridges, some stray wires, a pocket watch. It also contained every item he owned that DID explode. He actually had quite a few of the latter.
Unfortunately, he lost it all when he tried to rob a few wealthy lemurs. How was he supposed to know they would surprise him like that? How was he supposed to know the lantern would fall just the wrong way? How was he supposed to know the lemurs left so much of the gunpowder exposed?
Point is, he got out in time. The lemurs probably weren't so lucky. He lost the satchel, and everything in it. Except the pocket watch. This he treasures. It represents a lot to him. He hopes that when--or if--he recovers himself, he will be able to put the tired timepiece to use at last. That's worth looking a little silly.
....
SO QUIT LAUGHING! IT'S NOT A NECKLACE, IT'S THE FIRST COMPONENT OF A TIMER-TRIGGERED DETONATOR!
I SAID QUIT LAUGHING!
DON'T MAKE ME GET OUT MY FLINT AND STEEL! I'LL POUR LIGHTER FLUID ON YOU!
Ah, whatever.