I'm not allowed to carry around a boulder any more.
Dungeons and Dragons, Ed 1. Old school shit.
I had a boulder. The DM named him Earl and made him his own character sheet and everything, and started giving experience to the boulder, because he didn't want to give it all to me.
What I would do is hurl it down every hallway, and at every door. Any traps placed would be triggered, and I would get all the experience for both finding and disarming the traps, and I was leveling at an alarming rate because of it. The DM got tired of it, even though everyone else thought it was hilarious, and decided to make Earl his own character, and to give Earl all the experience for the traps.
Earl was level 30 when the rest of the party reached level 15.
The DM was very trap happy to try to counter Earl. But Earl always got the experience, because Earl would always hit the pressure plate/trip wire/magic rune/whatever, and always failed his agility roll to avoid triggering the trap (Due to being a big rock). Thus, the trap always went off, and always avoided harming the group. Discover, disarm. Done.
Thus, no more boulders.