The episode is, essentially, the story of a woman dealing with her ex-con ex-husband who keeps breaking into her house, and who eventually kidnaps her daughter.
On the other hand, it can also be read as an ex-con genuinely trying to reconnect with his daughter while slowly being driven mad... until it's revealed a restraining order was put in place before he went to jail.
Badass Bystander: Batman is (if only temporarily) subdued by a warehouse worker he startles. Upon seeing he just knocked around the Dark Knight, the guy is understandably terrified. Fortunately, Batman holds no grudge.
Butt-Monkey: One of the security guards who was trying to get into the locked bathroom (occupied by Lloyd and later Bruce). He waited by the door, until Batman came out and knocked him out.
Clothes Make the Maniac: Lloyd was already slightly unbalanced, but the invisibility suit became toxic when it was activated and apparently drove him completely over the edge into complete psychopathy.
Determinator: Lloyd. What more can you say about a guy who's willing to pose as his daughter's imaginary friend while stealing gifts for her, just so he can be close to her and earn her trust?
Dramatically Missing the Point: Lloyd thinks the money he stole with the suit will let him get back together with his ex-wife Helen. He never understands that she divorced him and is keeping their daughter away from him because he's an unrepentant criminal.
Dramatic Drop: When Kimmy tells Lloyd they're moving, he drops her doll in shock.
Flawed Prototype: The invisibility cloth bends light instead of reflecting it when an electric current is run through it, turning it and everything it covers invisible. In the process however, the plastic it's bonded with becomes toxic and thus too dangerous to use. With that said, it's never explained why the material was abandoned rather than being used for objects, like the car Ventrix uses. Likely even that could still be risky.
Kimmy: I was talking to Mojo/Batman. Helen: Oh, him again. Kimmy: But he really was here, mommy. Helen: I know, Kimberly. I know.
Noodle Incident: It's clear Lloyd has always been a crook, but exactly what he went to jail for in the first place is never detailed.
Not-So-Imaginary Friend: Kimmy's pal Mojo is actually her ex-con father in an invisibility suit. Later, she ends up talking to Batman, who leaves right before her mother walks in to ask who she's talking to.
Outside Ride: Batman grabs onto the roof of Ventrix's invisible car to stop him from kidnapping his (Ventrix's) daughter. The whole thing comes crashing past through an alley, leading a witness (who only sees Batman zooming along about four feet off the ground) to remark to another, "I didn't know he could fly too..."
Sanity Slippage: Ventrix ends up becoming more unhinged the longer he uses the suit, until he reaches the point where he doesn't care if it kills him—he just wants his daughter back.
Talking Is a Free Action: During Batman's initial encounter with Ventrix, he manages to expose him by covering with paint. Ventrix mocks Batman and activate his suit to clear the paint off, and Batman waits until after he's done this before trying to jump him, but naturally by this point he's moved out of the way and the Dark Knight simply ends up falling into wet cement.
Too Dumb to Live: Lloyd doesn't care if the suit is poisonous, just as long as he can use it to get his daughter back.
Tragic Dream: All Lloyd did, he did to be with his daughter... but when he reveals himself to her, she rejects him and wants to be with her mother. At the end, Kimmy told Batman she and her mommy will move and her father will never find them again. Lloyd could never be with her.
Villainous Breakdown: When Batman tries to warn Lloyd about the suit (and right before he gets defeated), Lloyd replies:
"Who cares if it is? With this suit, I can take back my daughter whenever I want! Her mother won't stop me, and neither will you!"
Water Tower Down: A variant where the water isn't used for a direct attack. Batman wins the final confrontation by tossing a batarang into a water tower so that the spray reveals Ventrix's position. With his one big advantage negated, he's easy prey for Batman's superior fighting ability.