Fish eat worms, we eat fish. Chickens LOVE worms, we eat chickens. We just get our worms another way
: As you've already found out, they're not bad, even if they DO have a huge gross-out factor.
Mabel may have even brought it in herself with a mind towards future play (or snack). Worms like nice, moist earth ... your house has nothing to entice a worm inside of its own accord. So it got brought into the house, one way or another.