Shmuktroid

The Shmuktroids are a race of mysterious creatures which inhabit the 8th Dimension, according to Grim's tall tale.

Biology
Two radically-different phenotypes of this species exist: a Grey-like humanoid form, and a gigantic purple-skinned monstrous form. The Grey-like Shmuktroids have a hunched, simian-like posture, proportionally short legs and large pointed heads with almond-shaped red eyes, blue lips and Human-like teeth. The giant Shmuktroids, on the other hand, have purple skin, black round eyes and sharp teeth. Only the Grey-like Shmuktroids appear to be sapient and capable of speech.

The relationship between these two forms is not clear. However, one of the Grey-like Shmuktroids has referred to the giant creature as "one of our daughters", which gives rise to two possibilities. Either it's a case of metamorphosis, in which the giant form represents the immature stage; or it's a case of sexual dimorphism, in which the males are Grey-like and the females are giant monsters. The latter seems slightly more likely, given that the Shmuktroids wanted to find a husband for their "daughter", possibly indicating that she was already a young adult.

Culture and society
When a newcomer arrives at the 8th Dimension, the Shmuktroids will welcome them and tell them to enjoy their culture and marry one of their "daughters". Unfortunately for the visitor, "marry" in this case apparently involves being devoured by the giant creature that the aliens refer to as their "daughters".

Appearances

 * The Grim Adventures of Billy & Mandy, s06e09, "Short Tall Tales" (2007)