Random Generator gave me Manabarbs and Stone Giant. I figured this was their spiritual successor. There's some weirdness in the text, since I didn't want players to tap all their land and target one creature they control. If you have 6 lands with this out, tap them all, and control a 3/3, a 2/2 and a 1/1, all your creatures will die. No escape clause.

Granted, this ability is really red-blue, but I'm going to pull a Vorthos defense here, and say the flavor is very red, so mono-red it is. Besides, with a little spare mana on everyone's part, this is pretty close to "All creatures gain -0/-1 and lose flying."

That is a wacky and very interesting idea.

("No escape clauses"? Hah! Lashknife Barrier, Light of Sanction, Darksteel Myr... but I know what you meant :) Interestingly, you might actually not want to use the first two, though, because the wording here means they won't gain flying. Nice.)

­I didn't want players to tap all their land and target one creature they control.

Because the choice of creature happens on resolution? It took me ages to work that out.

That's actually really clever, I've often wanted a "do bad things to your own creatures, but you can't cheap and put them all on the same one" clause. But it really doesn't work the way I expected, reminder text may be a necessity, even on an uncommon?

And the resultant card is really interesting, although I'm not sure how well it would actually play; may it just completely lock weenie decks out of contention, if you can't play another 1/1 creature while you have some already on the table?

Mostly true. But true weenie decks are kinda-sorta locked out of contention by their very nature. I mean, any deck that only features one toughness dudes will be knocked out by a single Tremor. Or, you know, Aether Flash, which people seem to keep designing around, thinking it's fair (I'm uncertain, myself.)

But, I don't disagree. I don't think the true weenie decks have a problem, since they can probably provide a couple 2-toughness creature flying... and that's going to be a very dangerous round 5 after you play this card. Those decks have light curves, so you could probably get around playing under this card's shadow. This is really going to hunt some deck, though. Chaining Captain's Calls into eachother is just plain silly. I'm upping this to 5 mana for now. It probably needs one more... but there's a point where the card doesn't really do anything, and I don't want to go there.