Splotch

Splotch is an evil, robe-like alien with plans for world domination. He was initially a sentient robe with a hostile attitude, but he later evolved after being dunked in toxic residue.

He first appears in "The Jarring Jerkiness of Judge J.O.R.T.S.".

Appearance
Previously, he appeared as a simple black alien robe. The robe sleeves serve as his arms, and the hood is his mouth, filled with rows of sharp teeth.

In "The Shadowy Syndrome of the Sinister Splotch", his appearance was changed drastically, now mirroring the look of Captain Underpants. He now completely matches the look of Captain Underpants, even having his cape. This form was however foreshadowed earlier in the episode, with the second form being seen as Mr. Ree's shadow through Splotch.

Personality
Previously, Splotch was a unnamed, trouble-making alien robe, who was very hostile, and would possess anyone who wears him. This was until he was knocked into the toxic waste that mutated him. He gains new abilities such as speech, lack of hostility, and having Captain Underpants' powers.