The JLU episode was the first time Alan Moore has ever liked an adaptation of his work, that alone makes it a CMOA for the entire JLU writing and production staff.
You can tell this is the case because Moore's name is actually in the credits; he almost always asks for it to be removed in adaptations.
It's also a rather twisted CMOA for Mongul who goes from B-Lister to a terrifying monster in the space of a single story arc, undoubtedly thanks to his rather impressive feat of defeating Wonder Woman and going toe-to-toe against a completely pissed off Superman.
"Happy Birthday, Kryptonian. I give you, oblivion."
When Batman (in the JLU episode) references Superman's defeating and humiliating Mongul. You can almost see him smiling while he's talking about it.
In general, Batman talking to Mongul just like he's your average criminal.
It's incredibly cool in both the comic and in the JLU episode when Clark breaks out of mind control. In the comic, he screams MONGUL! at the top of his lungs in a pure rage, releasing a loud enough yell to knock Jason Todd away. In the episode he doesn't make a sound, he turns, glares to where Mongul and Wonder Woman are fighting, and then he flies toward them as fast as possible, wrapped up in Tranquil Fury.
"He hears a voice like Armageddon shouting his name, and he starts to turn - he knows he has perhaps less than half a second in which to defend himself... but the rock of the far wall seems to ripple outwards in a sudden cascade of powder and a four-hundred-mile-an-hour wind slams into him like a steam hammer as big as the world - and he knows that he is far too late."
This exchange from Mongul and Wonder Woman in the weapons vault.
Mongul: Oh, dear. Is that a neural impactor? I didn't know that they were still making those. I'd advise you to try the plasma disruptor. It's more of a woman's weapon.
Wonder Woman: Go to hell. *SHBOOOOOOOMMMMMM!!!!*
The animated version has the gun firing cut off the "hell", which somehow makes it more awesome.
And then Mongul gets one for being completely unaffected by it, sporting a Psychotic Smirk.