Unknown critter?

I just looked in my tank and one of my clay pots I saw a small spherical thing... i thought it may be a cory egg, and quickly went online to find pics... when i went back to compare the real thing and pictures, it had moved.. then i looked closer and it looks a lot like a spider or.. something.. i can't tell at all.. i don't even have any idea where to look...

my tank is 10g lightly planted, sponge filter... 3 cories, 1 silver tip tetra, 1 colombian blue/red tetra... it's cycled with 0 ammonia and about .3-.4ppm of nitrites.. it's been that amount for a while now, so i don't know if it's ever going to finish dropping.. i don't think any of that matters, but whatever..

thanks... i'm just hoping it's not a snail or something, but like i said, it almost looks like a spider.... thanks

alright, i wasnt worried about it, just was kinda weird seeing it..

where does it come from? store bought plants maybe?

it's definetly not a hydra... i'm guessing it was a spider mite maybe? i did a google search and didn't find anything about them straight off, but whatever.. i can't even find it anymore so i'm not too worried