This ability doesn't trigger if you copy a spell that targets it, or if a spell's targets are changed to target it
The fact that it is much more of an early play really slows the momentum of an aggressive deck and winds up doing a lot more for you in those match ups when you play it at the start than a turn five Thragtusk will manage
Key pieces for a good Grima deck would be Strionic Resonator to double your thievery shenanigans, a good haste enabler through Swiftfoot Boots/Lightning Greaves as well as a way to punish your opponents such as Leyline of the Void or Dauthi Voidwalker
Meanwhile, the back face is Tergrid's Lantern, an artifact that points a gun at your opponent's head and forces them to either sacrifice a nonland permanent or lose three life
FIRST OF (SURPRISINGLY FEW!) BRIEF ASIDES: Very rarely will a site like SCG have a published price on a foreign foil or rarity
Being able to handle a threat is the core of "removal," thus a counter and a bounce and a board wipe must fall into this category