Singer of Swift Rivers is a rare Creature — Merfolk Shaman card from Magic: The Gathering (The Lost Caverns of Ixalan Commander, LCC). Current market price: $0.30.
Flash
When this creature enters, put a shield counter on another target creature you control. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)
You may cast Merfolk spells as though they had flash.