After looking at it, I was curious if this guy happens to be based on a scary face. I mean, I can see the parts on it; here's an example: The ship's wheel: eyes and nose Anchor and seaweed: mouth and teeth
Combine that, and you have a scary face. So was Dhelmise based on a scary face as well?
Dhelmise appears to be a cluster of seaweed holding together the anchor and a helm of a wrecked ship. Its behaviour may be a reference to two famous captains in classic literature, Captain Ahab the main protagonist in Herman Melville's Moby-Dick that dies tied to his own harpoon while trying to kill a whale, and the captain of the ghost ship Demeter, that in Bram Stoker's Dracula is found tied to the helm of the ship after being drained by the protagonist. The type of seaweed it is based on is possibly the Codium fragile, also known as "dead man's fingers". Dhelmise's concept as a seaweed-based monster is reminiscent of the works of William Hope Hodgson, particularly his Sargasso Sea Stories. It may also draw inspiration from giant and colossal squids, which are preyed upon by sperm whales.
Dhelmise appears to be a cluster of seaweed holding together the anchor and a helm of a wrecked ship. Its behaviour may be a reference to two famous captains in classic literature, Captain Ahab the main protagonist in Herman Melville's Moby-Dick that dies tied to his own harpoon while trying to kill a whale, and the captain of the ghost ship Demeter, that in Bram Stoker's Dracula is found tied to the helm of the ship after being drained by the protagonist.
The type of seaweed it is based on is possibly the Codium fragile, also known as "dead man's fingers". Dhelmise's concept as a seaweed-based monster is reminiscent of the works of William Hope Hodgson, particularly his Sargasso Sea Stories. It may also draw inspiration from giant and colossal squids, which are preyed upon by sperm whales.
Dhelmise (Bulbapedia)
Nothing is said about "scary faces". However, it is partially based off a monster, as shown.
Hope I helped!