Sister from another Mister Fantastic

[Olli]

If you read enough superhero comics from the Big Two, and others, you'll recognize the phenomenon: Publisher A has a cool character Bob, but there's a surprisingly familiar character Rob in Publisher B's stable as well... Which one was the original and which is the copycat? Let's list some pairings, and try to determine which one is the inspiration and homage in each couple (or triplet, or...).

I'll start with a couple of easy ones:
Original: Superman - Copycat: Gladiator
Original: Batman - Copycat: Moon Knight
Original: Catwoman - Copycat: Black Cat (hah)

 

[Octopus Prime]

Superman was also copied more overtly with Hyperion and The Sentry

 

[gogglebob]

What's the order? Darkseid - Thanos - Mongul? I'm sure it continues from there.

 

[Octopus Prime]

I’m fairly sure you can toss Apocalypse and Anti-Monitor into that sequence, too

 

[Johnny Unusual]

Original: Superman - Copycat: Gladiator

Funny thing about that.

 

[Adrenaline]

Namor predates Aquaman by a couple years, going the other way.

As far as more obvious and direct homages as opposed to veiled rip-offs, Marvel's Squadron Supreme (including Hyperion) are a clear Justice League pastiche, and DC's Retaliators are the same for the Avengers.

 

[Vaeran]

Copycat: Moon Knight

Let's take this outside.

 

[Daikaiju]

Shadow - Darkwing Duck

 

[Olli]

Funny thing about that.

That's great! You've clearly understood the point of the exercise.

 

[Felicia]

Is it possible that Marvel's The Sentry is inspired by DC's Triumph? They're both powerful superheroes who were retconned into having been important, beloved, members of the superhero community for a long time, but then being completely forgotten due to time-travel/mind-wiping shenanigans.

 

[Olli]

Nova is a flying space cop that belongs to a corps like Green Lantern, but the similarities aren't huge beyond the those points.

Deadpool was created as a riff off of Deathstroke. They look quite similar, but of course Pool is quite the personality of his own, and regenerates much better too.

 

[Büge]

What's the order? Darkseid - Thanos - Mongul? I'm sure it continues from there.

Well, both Thanos and Mongul were created by Jim Starlin, who has claimed that Thanos's design was more directly inspired by the New God Metron, and there is evidence to back that up. So, strictly speaking, the pedigree would go Metron -> Thanos -> Mongul, but I don't believe Mongul has inspired any copycats.

 

[Octopus Prime]

Mongal

 

[Jeanie]

There's always the similarities between Doom Patrol (debut June '63) and X-Men (Sept '63).