Does Stifle counter a fetchland's crack ability?

When you activate a fetchland (such as Flooded Strand), you pay its cost — tapping and sacrificing the land — and the activated ability goes on the stack. At this point, an opponent can cast Stifle to target and counter that ability.

Under CR 602.2, activating an ability involves announcing it, paying costs, and placing it on the stack as an ability object. CR 509.2 (for Stifle specifically) and CR 701.5 establish that countering a spell or ability removes it from the stack with no effect. Crucially, costs are paid when the ability is activated, not when it resolves, so the fetchland has already been sacrificed by the time Stifle resolves — you still lose the land.

This is the critical sting of Stifle against fetchlands: you sacrifice the fetchland as part of the activation cost (CR 602.2a), so the land is gone regardless. Stifle then counters the ability, meaning you do not search your library, do not find a land, and do not shuffle. You simply lose the fetchland for nothing.

Example: You tap and sacrifice your Polluted Delta, and its ability goes on the stack. Your opponent casts Stifle targeting the ability. Stifle resolves, countering the ability. You've lost the Delta, but you don't get to search for an Island or Swamp.

This interaction makes Stifle extremely powerful in formats like Legacy, where fetchlands are common, generating a significant tempo and card-disadvantage swing for a single blue mana.