Negative mana costs sounds cool, but it's not clear, and so it needs reminder text. At which point it stops being that cool, and you probably just want Burning-Tree Emissary's template on a -cost creature.

card's basically just a joke card. how can you make a lesser ornithopter (in the sense of lesser gargadon) when its CMC is ?

well, i guess it has to cost negative mana. this would be a terribly narrow ability in a real set, but for one card it's amusing enough

See also Motivational Piker :)

geez, and i thought i was being clever! ah well. on the other hand, having legitimate negative symbols is awesome

ah wait, nevermind; just read the comments. doesn't matter, i can tell what it does