Magma Cube

Magma Cubes, also known as Fire Slimes, are hostile mobs found in the Nether and have been released in 1.9 Beta, more commonly found near nether fortresses. When they move, they jump up and momentarily unravel into eight layers, giving them the appearance of a spring and revealing a molten core inside. An unique ability to these creatures is they don't drown in lava, but they can in water.