Counterflux is a rare Instant card from Commander 2015 (C15), collector number 214. Current market price: $0.65, TCGplayer market prices via Scryfall.
This spell can't be countered. Counter target spell you don't control. Overload {1}{U}{U}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")