Forgived, that's one of the smithing bonuses. If and when you fail to upgrade an item, you get a 50% chance to get it back at level 0 instead of having it be completely destroyed.
Protip: Larger missle and bomb batches have lower rates of fire. Supplementing grow hexes instead won't give as much damage boost, but they will retain their fire rate.
Grow + speed + bomb = lulz. Seriously this game has so much re-playability options it's hard to not play this game for hours.
Guys, while holes don't send you anywhere. They are pretty much black holes that work backwards.
WORMHOLES send you places. Believe me, I just flew into a while hole and died instantly.