Original card, based on the Leaping Lizard cycle.

I thought about using 'must block' here. But common has zero tramplers, so it made more sense in my mind to just use that.

Other than that, nothing special. Oh, I thought about using an undead minotaur here, but the blue creature in the leaping lizard cycle is already a minotaur. Would have felt weird. Plus this artwork works better as a black/green creature than any zombie minotaur I looked at anyway.

I like this, but something feels a little odd -- I think it's that, some of the other leaping abilities you might choose each turn whether to activate them, whereas if you use this, it's pretty much guaranteed that either this will die, or the creature blocking it will die, so the ability will usually only ever translates into 1 or 2 points of damage total.

Well, technically Money-Grubbing Minotaur won't get used every turn, but I get your point (I'm kind of hazy that people will like the Money-Grubber, too. But, to be honest, intentionally giving your own creature -1/-1 isn't sexy to begin with.) As a matter of fact, how you use the ability is different on Castigating Caste since one can use it twice (or maybe more times per turn with some boost) if you need to. There's no need to leap the lizard twice.

It's something to think about. Ultimately, this cycle has little to do with how the set as a whole operates. As long as they stick to their casting costs and don't go OP, I can kind of do what I want. I guess I want them all to have a similar feel to the Lizard... but I also don't want to end up with 5 evasive creatures. Red to white is likely to give first strike (assuming I don't do something really stupid and try to grant flash to the creature in my... nope. Time to stop talking about that.)

So, in theory, I would need a blue creature with a red ability, and a black creature with a green ability, no evasion, no hexproof or protection (plenty in the set already) that can be activated once per turn for positive benefit. And things like firebreathing don't really make sense (though, trust me, I thought about using "-1/-1: Target creature gets +1/+0." Seems silly, though.) Oh, and it would be a plus if I didn't have to change the flavor on either card while I'm at it. Hmm...

Seemed to have solved your problem by accident, Jack. It occurred to me that I wanted to add some poison to this set, to give Leeches more relevance. So this card is getting Infect soon, and you can, theorhetically activate it every turn (though, not for long, I suppose). Also keeps the Infect theme in black/green, which works for me.