They are much like slugs. Slimy, both sexes parts, and shaped like them.
They behave well, until angered. When angered they become triangular and make buzzing noises. They turn pink and orange.
When happy their yellow and green/blue. They are their normal shape, and basically just chill beans.
Sometimes they're all colors mixed. That's when they're tired, or just being mellow. They can choose shape at this time.
If sad, they turn completely blue. They become an oval, and sometimes roll around.