2018-12-07 : Marang River Prowler checks if you control a black or green permanent only as you begin to cast it. Once you begin to cast Marang River Prowler from your graveyard, it doesn’t matter what happens to the black or green permanents you control.

2018-12-07 : You must follow the normal timing permissions and restrictions and pay its cost to cast Marang River Prowler from your graveyard.