Samuel Guthrie, Cannonball

At the beginning of each combat phase, Samuel Guthrie, Cannonball gets +2/+0 and gains flying, and indestructible until end of turn.
X-Trait --- Whenever you cast your second spell
of the turn, Samuel Guthrie, Cannonball gains trample until end of turn.

Nice try, but Ah'm pretty much invulnerable when
Ah'm blastin'. You fellas wouldn't happen ta be invulnerable, too, would'ja?