Exposed as a criminal, sentenced to prison, and terminally ill due to long term kryptonite exposure, Lex Luthor escapes and assembles a supervillain team consisting of Cheetah, The Shade, Solomon Grundy, Star Sapphire, Copperhead, and Ultra-Humanite to take on the Justice League, calling themselves the Injustice Gang. The Joker also becomes part of the team, but on his own invitation. However, even with their combined power, this gang proves no match for Batman's wiles.
- Bad Boss: Lex's "leadership" of the Injustice Gang consists mostly of him yelling at his subordinates for their failures and name-calling. The Gang only puts up with his crap because he keeps offering more and more money. Somewhat justified since he did recently discover he had contracted terminal Kryptonite-induced cancer and wasn't in a particularly patient or forgiving mindset as a result.
- Bag of Holding: When Luthor gets a hold of Batman's utility belt the Batarangs and other gadgets that spill out of of the belt are far larger than any of the pouches could possibly contain.
- Chekhov's Gun: Green Lantern uses his ring to snatch a chunk of kryptonite away from Lex Luthor. Batman grabs it from midair and tucks it into his utility belt. Twenty episodes later, the kryptonite comes back into play when Batman takes it out of his utility belt to use as a weapon against Amazo.
- Decoy Damsel: A rather silly example in which the Ultra-Humanite is holding a hostage outside a government building to lure the Justice League there. The hostage turns out to be the Cheetah...which makes one wonder how the authorities who were already there didn't notice that his hostage had fur.
- Et Tu, Brute?: Lex Luthor was hit in his armor by Humanite with a "killswitch" device when the latter sneaks up behind him. His words being, "Et tu, Humanite?", before he went unconscious.
- High Heel-Face Turn: Batman convinces Cheetah to sell out the Injustice Gang to the Justice League, which earns her a Redemption Equals Death (though she gets better). Subverted when it turns out she didn't, and the real traitor was Ultra-Humanite, who didn't want to be there in the first place. And because Batman made a huge donation to National Public Radio in his name.
- I Resemble That Remark:
Hawkgirl: That's fast...
Flash: Fastest man alive!
Flash: Yeah. (beat) Hey!
- No Water Proofing In The Future: Batman shorts out Lex Luthor's stasis field by spitting a mouthful of water into it.
- Talking to Himself: Mark Hamill voiced both Joker and Solomon Grundy, who of course start arguing.
- Talking Your Way Out: Batman uses this method to escape the Injustice Gang. Features a very rare instance of the Joker being the voice of reason, as he anticipates Bats's strategy but is unable to convince Luthor to let him kill Batman. Even more interesting: Batman plays several cards at the same time, playing on Solomon Grundy's insecurities, playing the sympathy and sex appeal cards with Cheetah, and eventually delivering a bribe to the Ultra-Humanite (which Humanite donates to Public Broadcasting). Then, because he's Batman, he reveals at the end that he could have escaped any time he wanted to.
- Viewers Like You: The Culture Channel is used as a Brick Joke. The Ultra-Humanite is seen earlier in the episode enjoying an opera on the Culture Channel in prison, to Lex Luthor's displeasure. Later, when he's been paid off to betray Luthor, he donates it to the Culture Channel, leading to this hilarious parody of the line:
Announcer: The following programming was made possible by generous grants from the Ultra-Humanite and Viewers Like You.
- Why Don't You Just Shoot Him?
: You're not going to leave [Batman] like this, are you?
Joker: Hel-lo? He's still alive!
Luthor: And he's going to stay that way until I say we don't need him anymore.
Joker: Lex, Lex, take it from someone who knows: (whispered) don't wait, do it now.
Luthor: You don't like my decisions? Leave.
Joker: (Walking off) And they say I'm crazy...
(the rest of Luthor's gang stares at him meaningfully)
- You Get What You Pay For: Lex he will pay his Injustice Gang after defeating the Justice League. When he berates them for failing in their first attempt, the Shade tells Luthor you get what you pay for. In the end Ultra-Humanite betrays the team- since Batman guaranteed double what Luthor offered. And came through with a way to further twist the knife into Luthor: a major donation to Public Broadcasting in the Ultra-Humanite's name with recognition given at the end of an opera that drives Luthor nuts.