Zack, the Simplifier

This spell and its abilities can't be countered.
Whenever an opponent activates a creature's
ability by tapping it or spending mana for the
first time each turn, put a +1/+1 counter on
Zack, the Simplifier. This may trigger for each
opponent each turn. If a creature an opponent
controls has an ability get activated by tapping or
spending mana for the second time in one turn,
Zack, the Simplifier fights that creature.