Tidal Influence

Cast Tidal Influence only if no permanents named Tidal Influence are on the battlefield.

Tidal Influence enters the battlefield with a tide counter on it.

At the beginning of your upkeep, put a tide counter on Tidal Influence.

As long as there is exactly one tide counter on Tidal Influence, all blue creatures get -2/-0.

As long as there are exactly three tide counters on Tidal Influence, all blue creatures get +2/+0.

Whenever there are four tide counters on Tidal Influence, remove all tide counters from it.