"Pretend Circus!" is an episode of Oobi from the first season.
When the kids learn that they can't go to the real circus, they use their imaginations to play pretend circus. They become elephants and tumblers. They even imagine Grampu as a juggling, hilarious clown. — ABC Television
The episode opens in Oobi and Uma's room, where they have a poster advertising the upcoming circus. They spot an elephant on it and pretend to be elephants. Uma invites the viewers to imitate elephants with them. Kako mentions that he would like to be a circus ringmaster. Oobi adds that he loves the circus because of the talented acrobats. Uma tells the boys that she enjoys watching circus elephants most of all.
The children ask Grampu if they can go to the circus, but he tells them that it is located too far away and that they will have to wait. The children are disappointed at first. However, Kako gets the idea to create a pretend circus. He brings over a hula hoop and dubs it the "circus ring." He hovers the circus ring over them, and they find themselves at the pretend circus with Kako as the ringmaster. He introduces an unseen crowd to Oobi and Uma, who act as acrobats by jumping, flipping, and hopping on top of one another. Following their performance, they bow to the audience and ask the viewers to bow along with them.
After that, Uma pretends to be an elephant and Oobi wears a peanut costume. Uma chases Oobi until Kako introduces the next act, which features Grampu as a clown. Grampu repeats the phrase "Oopa-doo!" and attempts to juggle a ball, which simply involves throwing it and catching it. He later balances the ball and a flower on his nose, revealing the latter to be a trick. Grampu finishes the act by picking up a pie and balancing it. He bows for the audience, only to land face first in the pie.
Kako bids the pretend audience goodnight as Grampu calls them to the kitchen for lunch, and Kako lifts the circus ring to end up back in Oobi's room. Oobi says the circus is amazing, and Uma wants to say so too, but she has trouble pronouncing the word. After getting a little help, Grampu calls them to lunch. They are served peanut butter sandwiches, milk to drink, and pie for dessert.
This reminds the children of their circus, so they begin to chant "Oopa-doo!" and invite the viewers to join them, but Grampu is confused as he was not involved in the circus. Uma appears in interview segments afterwards, asking preschoolers if they have visited the circus. The episode ends with a circus-themed stop-go game, and Grampu coming in as the clown.