YAY-OK has one wheel to move around on, a rectangular body, and a screen for a head. YAY-OK also has a antenna on his head. He has a chest panel along with 10 buttons. His chest panel can open to carry the Rocket Monkeys, or to recieve any items from Dr. Chimpsky. YAY-OK has circles on each side of his head and lines under his eyes.
YAY-OK is very smart and he is quite the charmer. In fact, there is no ladybot that was on board that he hasn't made boop a little faster. But in the end of episode "Tail of The Unexpected", he become stupid.
Tasked with keeping the Rocket Monkeys on course, he likes them a lot and is there to help.
In "Princess Nefarious", at his first encounter with her, YAY-OK fell in love with Nefarious' robot Slo-Mo. He exchanged data with her and back on the ship they had a date and kissed. In "Party Planet", they went on a second date on Nefarious' asteroid, and later they went to the Council to Stop Supervillians' party, which was taken over by all the children.