All of the characters of PJ Masks are night creatures: Owlette, Gekko and Catboy.
This whole show has parodied Batman (1966-1968). Catboy's supersuit looks like Batman, PJ Robot acted like Alfred Pennysworth, The PJ Lookout is a parody of the Batcave, The PJ Mobile looks like the Batmobile, Romeo acts like the Joker, and the spinning clip referenced the Batman spinning clip from the 1966 series.
The villain Romeo is voiced by the same actor (Alex Thorne) who voices the part of Zuma on Paw Patrol.
The voice of Romeo also does a character on Paw Patrol.
The actor who plays Night Ninja (Devan Cohen) also provides the voice Rubble in Paw Patrol and Daniel Tiger in later episodes of Daniel Tiger's Neighborhood.