World Whelmer

At the beginning of each player's upkeep, that player returns five permanents they control to their owner's hand.
All lands are islands. Creatures with converted mana cost equal to or less than the number of islands their owner controls can't attack or block.
The storm it summons is so fierce that not even the beast itself can control it for long; to call upon its aid is to doom the world to a watery grave.