Creeped Out features a different antagonist for each episode, but some of them aren't exactly human.
Here are all the antagonists who appear in Creeped Out:
Marti: Marti, the titular smartphone
A Boy Called Red: No antagonist
Bravery Badge: Unnamed alien creatures
Spaceman: The titular spaceman, or Stan(named by Thomas)
Kindlesticks: The titular character.
Shed No Fear: The Shade
The Traveller: The Traveller