Bryozoans picture , about 25 mm high, on the side on my dock a few years ago. ..and usually repeating every summer. The coral of fresh water lakes.
Research is being done on this harmless plankton eating prehistoric deal.. for cancer cures.
The colonies start with a single near microscopic zooid, which asexually reproduces until it’s got an entire army of clones to hang out with.
Bryozoans are usually an indicator of good water quality, and should not be disturbed or removed from the water.