Air

Air (previously Bubble) was a lost bubble who appeared in "BMO Lost." After tumbling down a hill and cracking their faceplate, Bubble emerges from a broken mug and introduces itself to BMO, saying it had been lost in the forest for a long time, and was ready to give up. However, both BMO's determination to get home and the offer that Finn and Jake may help Bubble find its home restored Bubble's mood. By sharing multiple dangerous trials and spending a large amount of time together, Bubble and BMO developed a close friendship on their journey.