In K-ON!, Ritsu found a doll (belonging to Mio) of an old man who's almost bald with a huge nose.
If I'm not mistaken, it was shown when they were cleaning their club room.
(season 2, episode 2, 4:54)
Who is that old man doll? Was that doll based from a real person or from another anime or just a random creation from K-ON! itself?
This Japanese blog says it's a plush of "ウゴウゴルーガ" (Ugo Ugo Ru-ga).
I'm personally not familiar with the show, but the it strongly resembles おやじむし (Oyajimushi), which I think is an "insect father"? Whatever that means.
Searching further, this blog and this site agree.
Here's a picture of a plush doll that looks virtually identical, except for the nose being quite a bit longer.
And here's a Google search with multiple images for "おやじむし ウゴウゴルーガ" (Oyajimushi Ugo Ugo Ru-ga).
Among the images, there is one image from Amazon showing the manga where this character originates from:
The manga is titled おやじむしの人生 (人生いろいろウゴウゴ・ルーガ).
