Whenever I work out in the yard, I usually take a camera. You never know what you'll find! I have a couple of very large Devil's Backbone (a/k/a Redbird Cactus) plants that came with us from Texas 2.5 years ago, and the poor things have been in the same pots since then (I'm really terrible with houseplants!). When transplanting one into a larger pot today, I found a worm as long as my hand!
It's not unusual for me to find worms in houseplants. Back in Texas, we had a couple of really good potting soils to choose from. Rabbit Hill Farm had a wonderful potting mix, which often carried worm cocoons because of the worm castings, and Lady Bug Brand also had good potting mix. But it's been more than three years since those poor plants have had an infusion of new soil. Hats off to the giant worm for surviving that type of neglect!