A Fancy Creeper looks the exact same as a creeper, but wears a tall top hat.
A fancy creeper spawns in light levels 8 or above, but is rarely seen in the Overworld. If you're (un)lucky enough to find one of these buggers, you'd best have a diamond tool! They are only injured by diamonds, and even then, they have 14 hearts. If killed, they normally drop rarer items that would be found in a dungeon, abandoned mine shaft, or deep below the surface of the Overworld.