Creation and purpose
After Gamzee saw Dave's video of the Insane Clown Posse he went on a murdering rampage before meeting up with Caliborn. Gamzee made the puppet Lil Cal in which Caliborn liked as Caliborn saw darkness and evil in Lil Cal's presence. The only reason Gamzee summoned Lil Cal was to haunt Dave Strider so Gamzee could get his revenge on Dave for the Insane Clown Posse video. Gamzee then sent Lil Cal to do that.
It was eventually identified as a juju, a sort of container of power and an item with an ontological paradox existence, meaning he has no true point of origin.
Driving Dave insane
When Dave Strider got Lil Cal he thought Lil Cal was cool until Lil Cal annoyed Dave with puppets until Dave went insane and fought Cal. Cal eventually defeated Dave with the help of Bro. Later Cal appeared in Dave and Rose's dream in Derse's moon, taunting them. Rose then threw Cal out of a window were Cal fell but landed on a flying vehicle.
Lil Cal and the Trolls
After Jack Noir's rain of terror, Lil Cal, Bro, and Davesprite fought Jack until Jack prototyped and killed Bro. Jack then took Lil Cal as his "treasure" and flew away. When Jack terrorized the trolls he threw Lil Cal at one of the Aradiabots. The Aradiabot teleported away with Lil Cal but accidentally teleported to a place were a meteor hit them and blew up the Aradiabot as well as rip apart Lil Cal. Lil Cal was then handed to Sollux, who handed him to Kanaya, who handed repaired him with a costume based off of The Felt. Kanaya then handed Cal to Gamzee
Possesed by Lord English
Later Lil Cal was possessed by the spirit of Lord English. Gamzee gave Lil Cal to Jack with a note saying "YOUR MOTHERFUKING WELCOME!" When Jack looked at Cal, he was possessed by Lord English and turned into Union Jack.