Clayface is falling apart, literally. His clay-like body is disintegrating. Fortunately, a scientist he knew from his movie star days is working on a remedy. However, Hagen is forced to steal money to pay for the expensive components of the remedy.
"Mudslide" was written by Alan Burnett and Steve Perry. It was directed by Eric Radomski. It originally aired on September 15, 1993.
At Tarnower Financial, a middle-aged guard goes to check the parking lot while his much younger colleague, Billy, keeps watch at the main entrance. The old guard returns a minute later, however, having forgotten to check Mr. Tarnower's office. However, as he goes into the lift, strangely sweating, Billy sees the guard in the parking lot on a security camera, meaning that the guard in the lift must be an impostor.
Billy sets off the silent alarm and gives chase and catches the impostor in Tarnower's office, breaking into the safe behind a portrait of Tarnower. However, from the behind the portrait emerges Tarnower himself, berating Billy for leaving the door unguarded, but Billy suddenly remembers that Tarnower is missing his accent and actually on holiday in Hawaii, prompting Tarnower to extend his arm and knock Billy out.
Before he can finish Billy, Batman appears. The impostor takes on Billy's appearance and tells Batman he caught a thief, but Batman examines Billy's body and finds a strange, clay-like residue on Billy's body. Realizing who the impostor is, Batman turns around, but is knocked down by a mace made of clay. Indeed, the impostor is Clayface, having finally resurfaced. Clayface, however, does not finish Batman, but instead flees the building.
Batman gives chase and notices Clayface quickly losing his energy and leaving a trail of clay wherever he goes. He offers to help Clayface become human again, but Clayface, assuming that Batman will likely send him to Arkham Asylum for the treatment, refuses. Clayface finally collapses onto a bin and starts to melt away until his colleague, Stella Bates, arrives in her car and rescues him.
Stella takes Clayface to her laboratory and uses a machine to put him in a plastic coating to keep him together, a procedure which knocks him out cold for a while, until he wakes up and lashes out at Stella for watching an old movie of his, ashamed of his former self. Clayface immediately apologizes, and Stella shows him a way to increase and restore his powers, allowing him to take the form of Matt Hagen permanently: an isotope called Mp40, the only source of which is found at Wayne Biomedical Labs. Willing to risk his life, Clayface vows to remove the plastic coating and steal the Mp40 from Wayne.
Batman, meanwhile, takes a sample of Clayface's body back to the Batcave, and learns of Clayface's condition. Also remembering Stella from the Tarnower Heist, Batman tells Alfred to look through Hagen's career records for any sign of a relationship with a female doctor.
An intrusion occurs at Wayne Biomedical Labs, and Batman and finds Clayface, disguised as a woman, fleeing the building with a canister of Mp40. He pursues Clayface onto a train, where Clayface's body starts to give up again, and he "melts" back into his own form, scaring the passengers out. Batman and Clayfce then fight alone, until Batman sprays Clayface with a freezing gas to get the canister back, but Clayface jumps out of the train window and lands in a truck's cargo hold, breaking into pieces. Nonetheless, Clayface has succeeded in getting the Mp40.
Batman returns to the Batcave, where he and Alfred finally learn the identity of the female doctor from Hagen's movie Dark Interlude (the movie Stella was watching), and Batman finds her location in the bank's records, tracking her to her laboratory by the ocean.
At the lab, Stella starts pumping the Mp40 into Clayface, who is once again inside the plastic coating. Clayface demonstrates the Mp40's success by attempting to transform back into Matt Hagen, which he almost does until Batman arrives and turns the machine off. Batman taunts Stella and Clayface for their carelessness, trying once again offer them a better way. Stella lunges at Batman, only to smash headfirst into a pile of test tubes when Batman dodges. Clayface, losing control, breaks out of his coating and proceeds to absorb Batman, hoping to drown his enemy. However, Batman uses his grappling gun to blast his way out of Clayface's body.
Batman and Clayface fight again, and take the battle outside. The rain weakens Clayface, giving Batman the upper hand. However, Clayface, determined to kill Batman at any cost, pushes him off the cliff, only to have Batman pull him off as well. Batman holds on with a Batarang as Clayface is barely able to hold onto Batman's leg. Batman tries to hold him, but Clayface accepts his fate as his arm breaks, sending him plunging into the ocean below where he dissolves. At the edge of the cliff, Stella mourns Clayface as Batman takes her to the authorities. - DCANIMATED.WIKIA.COM