Aetherling

[Cakeisfun]

Is it possible to make aetherling larger than a 8/1 or a 0/9?

[gtfotis]

If you enchant it or buff it for the turn, yes. Also, you could make it's toughness as high as you want if you have the mana for it, it can have negative power.

[Pirate John]

You can keep increasing his toughness, but you can only increase his power until his toughness drops to 1. If it drops to 0, he's dead

[Gorzo]

You can give it -1/+1 as many times as you want. Power can go to the negatives and it won't matter. -10/19? Sure, if you have the mana, you can do that.

As for +1/-1, it's like everyone is saying above. As soon as toughness hits 0, it's moved to the graveyard as a state based action. You'll have you use auras, +1 counters, or buffs like {Giant Growth} to give it more toughness that you can take away from in order to keep using the ability (and surviving).

[Destore117]

So give it something where it has a steady stream of counters? Maybe some thing that gives it a counter each turn?

[Anoobass]

I don't see the help in giving him counters or auras or such because when you flinch him you lose all that, just seems pointless.

[Pleeb]

You lose it all when he flashes, but there are no rules saying you can't. It could provide a timely extra boost just when you need it.

[Avnger345]

Bestow him, then when he flashes, you still get a creature in aura/enchants place