Crumena, the Shadow Keeper

Crumena has every activated ability of creatures in all graveyards. Whenever Crumena becomes tapped to use an activated ability of a creature in your graveyard, untap Crumena, the Shadow Keeper.
{b/g}{b/g}: Create a 4/4 Golem with First Strike.
"I crave knowledge, and never before
has yours been so...lacking."