50 Cent -- We Gon' Party Like It's Your B-Day, Son ... Even In Costume

When there's trouble, 50 Cent's kiddo knows who to call -- Mom, Dad and the whole Teen Titans crew ... especially when it's his birthday.

50 and Daphne Joy threw their son, Sire Jackson, an epic Teen Titan-themed party for his 4th bday over the weekend at L.A. River Studios ... and they went all out for their boy with an event from "The Wife of the Party," a company run by Loriann Serna.

Check out the pics. Fitty rocked a Cyborg costume, Daphne donned a purple dress as Starfire and his grandma and aunt were Robin and Raven, respectively.