Zebra mussel (Dreissena polymorpha)
https://www.dnr.state.mn.us/invasives/aquaticanimals/zebramussel/index.html

Zebra mussels (Dreissena polymorpha). Photo: University of Minnesota

Zebra mussels. Photo: Megan M. Weber.
https://www.dnr.state.mn.us/invasives/aquaticanimals/zebramussel/index.html