Systems and methods are disclosed for enhancing the processing of hydrocarbons in a FCC unit by introduction of fluidized plastic at one or more locations of the FCC unit. In an embodiment, the method may include passing a coked FCC catalyst from a cyclone of the FCC unit to a regenerator. The method may include introducing at least oxygen and a fluidized plastic into the regenerator. The method may include combusting a combination of the fluidized plastic and a coke from the coked FCC catalyst in the regenerator, thereby to oxidize via the oxygen and produce a regenerated FCC catalyst and a flue gas. The method may include supplying the regenerated FCC catalyst from the regenerator to a riser of the FCC unit to crack the gas oil supplied to the riser of the FCC unit.