Toltep walked slowly along the avenue, it would have been easier to swim along in the viaduct, but he had made it a point to not do the easy thing. All to often the easy path lead to ruin, and he had not survived so long by taking shortcuts, or the easy road. The market, what was above water, was abuzz with conversation. A large school of blood-crazed lurdi had been diverted into an ambush where the brave people had slaughtered the monsters. There was some worry, Toltep gathered, as a few had escaped.
Foot Coral. It attatches to a foot like moss, almost gluing itself to an organism. It gets its food supply from the ground, and does not leech off the host in any way. It is not a malignant organism, and is entirely harmless. But it only grows on human feet, and even then, never on the left foot. An organism that it grows on can feel touch through the coral, but not pain. Removal of the coral is painless, but why would you want to?
Texturally, if fells like a dry, non slimy amoeba.