It is unknown in which comedy Cameo first appeared, but it would seem to be prior to his first appearance in Ga-Metru School Musical. He is described as a Le-Matoran and apparently likes appearing briefly in comedies (hence his name) and pulling pranks on certain characters. He is most often seen in GMSM, GMSM2, and Lewa0111's School of Comedy.
Cameo's running joke, unlike most of these, is not triggered by any particular line or event, instead, he appears as a result of one of several triggers and does something depending on what triggered his appearance. For example, in the Ga-Metru School Musical series, he appears whenever Jaller and Hahli are about to kiss, throws various electrical appliances at the couple, and shouts "Ha, ha!" before disappearing. In L#SC and other comedies, he is usually seen after a character uses the :wub: emoticon and is called on it, to which they explain that Cameo dumped a large bucket of pink paint and heart confetti on their heads. Sometimes, Cameo will actually be seen running away with said bucket.
Cameo has also made a Guest Starring appearance in Turakii's Bionicle Romeo and Juliet, alongside Tava.