That's... a terrifying creature. For the cost of a craw worm, it's tougher, it tramples, AND it probably kills a creature a turn in addition to whatever its attack does.

Still, red DOES get 6/6 +bonus for rr4. They're just terrifying!

This looks like a mythic. It's comparable to Inferno Titan; this isn't quite as good as the Titan, but that's good because the Titans were, shall we say, at the top end of where creature strength should be. (Or breaking through the roof.)

­Pyrovillian Foot-Soldier needs watering-down, and this is an uber version of it. Do they need a restriction of making their ability only on your turn, or (since it only affect creatures) is it good as-is?

I think I like this with the only-your-turn restriction as well as once-per-turn, but it could go either way.

I just realized: if I activate the ability after blockers are declared, he can effectively become an 11/6 trampler, which is way too much epicness for 6 mana.