Study counter

Study counters are a type of counter introduced in Stronghold. They have been used in various sets for various unrelated effects.
==Description==
Study counters first appeared on <c>Pursuit of Knowledge</c> in Stronghold. It was an enchantment that allowed for the skipping of a draw to add a Study counter. Once three Study counters were accumulated, they could then be sacrificed in exchange for seven cards to be drawn.
Innistrad saw the return of Study counters on <c>Grimoire of the Dead</c> which allowed for a counter to be placed in exchange for discarding a card. At three Study counters, it could then be sacrificed, which moves all creatures from all graveyards onto the battlefield under the player's control as a Black Zombie on top of existing colors and types. 
<c>Kianne, Dean of Substance</c> was the first creature to use Study counters. One could be placed on non-land cards exiled by her first ability. It then had another ability to create Fractal tokens with +1/+1 counters equal to the number of mana values among the exiled cards with study counters. exiles X cards off the library with Study counters on them and puts one into hand; the two synergize with Imbraham putting study counters en masse, including lands, which guarantees another value for Kianne's Fractal ability. Conversely, Kianne's exile ability gives a faster and cheaper selection for Imbraham's card ability.
Alchemy Horizons: Baldur's Gate had <c>Vhal, Eager Scholar</c> which is a digital-only card that uses Study counters for effects of the Specialize mechanic. After specializing, the counters were removed and a scaling effect occurred based on how many were on it.
==Trivia==
*In Magic Online, the counter is colored green as it's considered a positive effect and shares its icon with Filibuster, Landmark, Level, Lore, Page, Plot, Quest, and Story counters.
==References==