Bel'Enion, the Odd One Out

Suspend 4 — {1}{u}
When Bel'Enion enters the battlefield, if you
cast it from exile, Merfolk you control have base
power and toughness 3/3 until end of turn.
Threshold — As long as there are seven or more
cards in your graveyard, Merfolk you control
have islandwalk.
"The Waves will take you!"