What would even be the best target for this?
One of the meld creatures? Then the spirit would meld and you'd still have the body?
Jhessian Thief just to have a flier prowess card drawer?
One good one is
Walker of the Wastes. The 1/1 flyer has trample and a boost per Wastes, so it's only 3/3 loss to gain flying, but you also have a 4/4 just because.
I can think of two general ideas, but not sure what to specifically use.
First, it's 8 mana overall, but the 5 for the actual action is at instant speed. What's a great setup at instant speed?
Thalia's Lieutenant?
Woodland Bellower?
Second, what's a large creature with a killer "sacrifice this card to..." ability? Because you can then sac the 1/1 and keep the large zombie. Or a good "when this dies" that you can throw away the 1/1 easily?
Seed Guardian? (Not Greenwarden, that's a wash, you skip the 2nd return ability to leave him in the graveyard, and the can only use the 1/1 enters play not the when dies part.) I almost want to do this with
Breaker of Armies so the 10 power hits and the 1/1 is the decoy, but the flying is actually working against that.
Well, I know it's not sexy, but how about
Bloodpyre Elemental? Turn 5 you use it as removal, turn 6 you pop the
Soul Separator to make a spirit token that also sacs to deal 4 to a creature, and you still have a 4/1 zombie. That's some serious back-to-back removal that leaves you with a board presence.
However, my vote has got to be for
Endbringer. Ever since I first saw that guy, I've wanted to divorce those tap abilities from its giant body so I could also use it for combat more often. Now they can go on a little 1/1 spirit token, while the 5/5 zombie brings the beats / stabilizes the ground.