Jake (aka Randy Butternubs)
Jake (full title: Jake the Dog), the deuteragonist of the Cartoon Network original series Adventure Time, is a magical dog and Finn's constant companion, best friend, and adoptive brother. Jake has a unique set of abilities called Stretchy Powers that allow him to manipulate the shape and size of his body, coming in handy on innumerable occasions throughout his and Finn's adventures.
Jake is generally laid-back and tends not to worry about things. He relies heavily on his powers (or Finn) to get him out of any dangerous predicament. While he often cracks jokes at serious times, Jake always has a lecture or a song to cheer Finn up if he is feeling disheartened. Acting as Finn's world-wise mentor, Jake is always willing to give input and advice about a situation, but his suggestions are usually inconsistent, ranging from encouraging and helpful suggestions to ridiculous nonsense. He can be somewhat irresponsible at times, frequently leaving Finn to fight most of a battle on his own, but he always pulls through when he is needed most.