One of my favorite works are the Cthulhu Mythos, which is a collaborative effort by the late H.P. Lovecraft and other contributors. Much like the Trevor Henderson mythos, we have different eldritch monstrosities like Cthulhu, Yog-Sothoth, or Father Diagon and how humanity is an insignificant existence within the larger, cosmological forces. One of Lovecraft's creations goes by many names but is prominently known as Nyarlathotep. Nyarlathotep is the son of Azathoth and serves as a messenger for the Outer Gods. Unlike his brethren, Nyarlathotep is human-like in his thought processes and is actively evil in comparison to the more unwittingly evil gods. As such, he considers mankind his greatest toy to play around with.
Nyarlathotep has over a thousand forms but is often known to appear as a jovial, tall man. Now think of the Man With the Upside-Down Face. Often he is depicted as wearing black attire. Jovial? Doubly check for the Man With the Upside-Down Face. His default expression is his upside-down smile and given how much he enjoys making people suffer in the different accidents, this does seem to lean towards the implication. With how the Man With the Upside-Down Face functions, he is a supernatural parasite who leeches off negative emotions like pain or grief.
But then there is also the Cartoon Cat. Given how Nyarlathotep has several forms, him perverting a 1930s style cartoon character makes some sense. Cartoon Cat also falls under most of the defining traits: tall, cheerful, etc. Much like the Man With the Upside-Down Face, Cartoon Cat appears to have some understanding, even if basic, that he comprehends humanity but instead of doing what the Man With the Upside-Down Face does, the Cartoon Cat instead hunts his food down, but all while still possessing a wide, sinister smile. Most of Nyarlathotep's forms also have animal-like attributes to them so him taking the form of a large, anthropomorphic feline is plausible.
