Flash-bomb Recipe
Artifact
{1}{r}, {t}: Deal half X damage rounded up to up to X target creatures and goad those creatures. X is equal to one plus the number of untapped nontoken creatures you control.
Marcy discovered that with a dollop of Heron's Bane, her generally flashy potion was able to be extra explosive.
As for the second ability, I'd restrict it to just destroy artifacts. That alone is good enough for a repeatable effect, and destroying lands is way too good for a repeatable thing to do.