Adaptation Displacement: Eddie Murphy's take on the character is much better known to modern audiences.
Well... maybe and maybe not. The Gumby Show was popular in syndication well after those sketches ended. Also, there was a new series soon after. To what do you think kids would have had more exposure back in the 1980s?
Faux Symbolism: The official companion book, Gumby: the authorized biography of the world's favorite clayboy, written by Art Clokey and others. Basically, Gumby's mind is free.
Hate Dumb: Sadly, Gumby gained one on YouTube, when Ray William Johnson released a video about a black guy playing Madden '11 and yelling, "FUCK YOU, GUMBY!!!" (The black player is actually referring to another Madden player and not the clay character himself).
Ho Yay: This may be a bit of a stretch, but has anybody noticed that Blockheads G and J are never apart? And that J seems to take G's abuse a bit too submissively?
Special Effects Failure/Off-Model: In certain scenes in which Gumby and the other characters walk or drive into a book, the animators used different models for the characters and vehicles. And these models were either crudely made or 2D!
The same goes for the shrink/growth episodes. In the 1960s episode "Chicken Feed", the growing effects with Tilly the chicken are created with badly colored two-dimensional pictures of Tilly. Also, in the 1980s episode "Shrink-a-Dink", the growing/shrinking scenes (specifically with Gumby, Goo, Prickle and Professor Kapp) used crudely made models in each frame.