It was the main driving point in Operation: H.O.M.E. when Numbuh 3 brought it along with her while her sector was on a mission. When they were supposed to capture Count Spankulot, who escaped when My First Rainbow Monkey was slapped and tore apart. The team had rushed to Numbuh 3 as she screamed, allowing Count Spankulot to get away.
Upset the next day, Numbuh 3 stayed up in her room and tried to sew her doll's head back with a heart-shaped button. Numbuh 1 comes in and tried to cheer her up after scolding her for letting Count Spankulot get away, trying to convince her to give up the doll. Numbuh 5 attempted to cheer her up with Rainbow Munchies (with 20% more sugar), when Numbuh 3 spotted an ad for the Rainbow Monkey Retirement Home on the back of the cereal box.
After visiting the estate, Numbuh 3 said an emotional good-bye to her First Rainbow Monkey and left with Numbuh 5, who tag along with her. Numbuh 3 started to freak out the next after seeing a heart-shaped button (the same one she used to sew onto her First Rainbow Monkey earlier in the episode) in her rainbow munchies, because she thought there was something wrong with him and dragged Numbuh 5 along with her.
It turns out Nurse Claiborne (from Operation: P.I.N.K.-E.Y.E.) had shredded it to make Rainbow Munchies taste better by making it out of real Rainbow Monkeys, but she sewed it back together (forced by Numbuhs 3 and 5), along with the rest of the Rainbow Monkeys as Numbuh 3 happily reunites with it.
My First Rainbow Monkey is a light-purple colored Rainbow Monkey with a long white a beard, pink glasses, and it is tattered a little bit due to its elderly form.
- It is ironic that the Rainbow Monkey aged, as almost no other Rainbow Monkeys have been shown to age.