Backchannel Swimmer

Suspend 1 — {w}{u}{b}{g} (Rather than cast this card from your hand, you may pay {w}{u}{b}{g} and exile it with a time counter on it. At the beginning of your upkeep, remove a time counter. When the last is removed, cast it without paying its mana cost. It has haste.)
Whenever you remove a time counter from Backchannel Swimmer, proliferate.
Hexproof, menace