Heating/Cooling Magma Cube Mechanic

Magma Cubes should have different temperatures. When they are colder, they harden and look the way they normally do. But when they heat up, they turn more liquid, looking more like red/orange/yellow slimes. When they jump they don't split apart, they just stretch like slimes do. Colder Magma Cubes sink in lava, but once submerged they start to heat up and rise back to the top, giving them a sort of lava lamp mechanic.