Mantis is one of the four major characters of the in-universe parody series "Cow Duck Avocado Mantis, meant to be an alternate version of Cricket. Ironically, Mantis was intended to be Cricket's original name.
Mantis is shown to be the nerdy member of the quartet, similar to Cricket's personality. However, his personality (like the rest of the quartet) is exaggerated to a certain extent.
Mantis is similar to Cricket in looks, but he wears a pair of round black glasses and wears a bowtie on his neck.