Beastly Bumblepuss is a frozen bean scout that Samson chats with. His only appearance was in the episode Cave Chatter.
Samson found this caveman frozen in a block of ice, and began talking to him as a friend, since the caveman couldn't tell Samson to be quiet. The Jelly Beans found him by accident, and when they saw the caveman wearing a Bean Scout cap, they wanted to thaw him and show him around camp. They called him a Cave Bean, the first Bean Scout, from which all Beans are evolved. After the caveman goes berserk and attacks the camp, especially seeking out Samson for driving him nuts with his incessant chatter, the Jelly Beans refreeze him. Once he's frozen again, Samson resumes talking to him; as the scene fades out, we see that it still drives the caveman insane, but he has no recourse.