Kazen Tidecaller

Stealth (This creature can't be blocked except by creatures with vigilance or creatures with equal or less
power.)
When Kazen Tidecaller attacks, put a tide
counter on it, then tap target nonland permanent
defending player controls with converted mana
cost equal to or less than the number of tide
counters on Kazen Tidecaller. It doesn't untap
during its controller's next untap step.