Bumble Hums

Bumble Hums is the name given by the Narrator to residents of Upside-Down Town in the episode Ultimate Upside Down Cake because they say "Hum" instead of "Yum". The Bumble Hums are Bumble Nums with gray skin tones instead of bright colors like the main characters. The Bumble Hums have a grumpy expression and wear drab, uniform clothes.

After eating some of Yeti's birthday cake, the Bumble Hums transform into happy, colorful Bumble Nums.