strange hitchhiker

[Iveman]

so i bought a pound of calurpa today (no cheato anywhere in town) as im setting up a fuge in a few days. i threw it in my display tank, no big whoop, and i see a few pods. cool. then i see what looks like a clear turbo snail, maybe a little bigger than a pod. still cool. then i see what looks like an inchwork with a pot belly. not so cool. it moves like an inch worm by pulling its tail to where its head is (making a U shape) then stretching the head forward. it kind of looked like a mantis shrimp at the head. i saw what looked like claw like appendages bu it was so small i could have been wrong. then i saw another worm like guy, only smaler. then another. should i worry? i would have taken a pic but i have a 1 mega pixel fisher price digital so thats that. any ideas??