msem-instigator

Barbed Reef enters the battlefield tapped. When it does, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this, then you may mill that card.)
{T}: Add {B}.
{4}{B}: Barbed Reef becomes a Jellyfish creature. (This effect lasts indefinitely.)