Crastrums

Anatomy
Crastrums have two basic tissues, a photosynthetic tissue which acts as a cover for the organism, and a steam tissue which changes the temperature of water inside it to expand or contract in size and acts a muscle.

Behavior
Most crastrums use a suction cup found on their underside to stay in one spot, they will swim in a pumping motion to get away from danger.

Diet & Energy
All crastrums have photosynthetic cells and use light to produce food, but one line took up a parasitic lifestyle and fed on blood, and another filter-feeds.

Locomotion
Crastrums move using steam-powered muscles, since these muscles rely on heating and cooling crastrums so far move rather slowly.