This is Christopher, he's an axolotl clown and also a middle school math teacher.

The top design is his "Lol Mode", which is the form he is almost always seen in. The bottom design is his "Serious Mode", where he turns much taller and starts destabilizing the fabric of reality. If he changes into this form, start running.

He also likes to break into random homes at night and steal food. While he usually just finds a random place to raid, sometimes he'll choose a specific person's house and attack them in their sleep as well if he doesn't like them.