­Heavy Arbalest as an aura. Quite cheap, but I guess the Arbalest is much better for being able to be moved around.

This is partly just a design sketch as part of an upcoming article, but I honestly would have no idea how to cost it, as even in a set with Rhythm it looks awfully narrow.

Humm. Well, at it's very worst, it's shock that requires you to effectively sac a creature. At it's best, it's a repeatable shock. (Creatures with love this stuff...) ­ is probably about right, maybe slightly more. It's not like "Lets you tap to do something good" is particularly difficult to find, although this is nice it's the setting up of the combo-of-doom that would make it hideous.

I don't think it could be costed less than , although it does require you to have a creature to give up, and doesn't grant haste, so it isn't a lock-down type card. So mayyyybe. (The real problem is that you probably don't want this ability to leak to all colours. So it'd have to be something like 'if you control a mountain you may cast this for free')

It seems to me that the easiest solution is to just increase the amount of damage it deals. If it dealt 3, it would just seem like an odd Lightning Bolt-style card. If it dealt 4 damage, you could start increasing the casting cost, or, preferably, give it an activation cost, so the combo decks have to work for it. If this card cost , activated for , : and dealt 4 damage to a creature or player, I'd nominate the thing to be put in the common slot, of all places. Of course, that depends on how destructive it is with the rest of the cards in your set. I haven't really looked at Melody with a critical eye. If there's an "untapping things matter" than you obviously have to be more careful.

There is, in fact, an "untapping things matters" theme rooted in an extrapolation of effects centered around the Rhythm keyword primarily found on blue and green creatures.

Mmm. That is trickier. How about an untapping penalty, then? Something like "Whenever this creature would untap, pay or it does not". I'm pretty sure that that doesn't really work, though, since you're not allowed to do anything during the untap step. Hmm...