in this evening's game of nethack, my pet dog got polymorphed into a purple worm via a trap and this has been the most hilarious run i've had in ages. only downside is it tends to eat the shopkeepers right off the bat so it's hard to sell loot, and i don't have a leash for it yet
all of the most annoying and run-ending monsters get vacuumed up by the worm and i just have to worry about hauling loot around and grinding levels to hit mid-game quest.