Lumpy is an unintelligent cornflower-blue moose with clean teeth pranging out of his mouth, bright disorbited eyes, mismatched antlers, and tremendous stamina second only to that of Splendid. Lumpy is one of the four primary characters in the series along with Cuddles, Giggles, and Toothy. His low intelligence is often the cause of other characters' deaths, and sometimes his own. His deaths also tend to be particularly drawn out and painful due to his ability to survive injuries that would kill most other characters instantly.
He is the only one of the characters with a standard nose with two nostrils (smaller Happy Tree Friends have heart-shaped noses except Sniffles who has a trunk). Lumpy has appeared in more Happy Tree Friends episodes than any other characters. Lumpy has had many occupations in many episodes, including a teacher, ticket clerk, bus driver, convenience store owner, police officer, physician, grave digger, firefighter, magician and more. He is usually a fill-in character, and often shown in tremendously incongruous situations, such as lounging lazily in a hammock, while the rest of the gang are playing. However he shows some intelligence in "Peas in a Pod" where he is cloned. He is often considered the "odd man out" because he doesn't share any Happy Tree Friend common traits such as a heart nose, buck teeth, or Pac-Man pupils.
He lives in a trashy trailer, frequently eats sandwiches and he likes to talk to lettuce#1. A rock on Mars was named after him#2.
Lumpy was voiced by Rhode Montijo for the first two seasons and is currently voiced by David Winn.