What was the name of this Muppet?

[Flaky Pudding]

I vaguely remember a character from what I think was something Muppet-related that I can't quite identify (it could've been something non-Henson but still heavily Muppet inspired like Eureeka's Castle though).

The character I remember was either a monster or an alien of some sort. It looked like a mix between a Snowth, a Blue Meanie from Yellow Submarine, and a Birdo from Super Mario. I believe it was supposed to be another character's imaginary friend a la the original version of Snuffy but I could be wrong about that.

I only remember seeing it one time so it was probably just created for one specific episode and was mentioned again afterwards.

That's all I can remember of this obscure creature and if anyone could help me remember the name of it, much thanks would be appreciated.