Cuddles is one of the main characters of Happy Tree Friends, and one of the four primary characters of the show, along with Giggles, Toothy, and Lumpy. He is considered the original Happy Tree Friends character and also the show's (unofficial) mascot, despite Shifty being created first.
He is also the yandere to Giggles.
in "Youtube 101: Subscriptions" is anything to go by, wherein he was furious when he thought Giggles dated Disco Bear. In that same episode, Cuddles is shown to stalk Giggles over the internet.