i thought it was black algae and tried to swish it and pick it away but it didnt budge and felt slimy. a few days later it started to change appearance a bit. it hitchhiked on a zoa frag we got when we went to tampa for the aquaculture farm. supposedly they only come from hawaii, so thats kinda cool to have a sorta rare sea squirt. i cant get a good photo yet but i'll show you guys someday. its very small right now. i also found a weird snail that looks like the snow cap candy. it's so cool the creatures that we find in our tanks...anyone have some cool stories to share?