Unnerving Assault is a uncommon Instant card from Eventide (EVE), collector number 114. Current market price: $0.13 (foil $0.47), TCGplayer market prices via Scryfall.
Creatures your opponents control get -1/-0 until end of turn if {U} was spent to cast this spell, and creatures you control get +1/+0 until end of turn if {R} was spent to cast this spell. (Do both if {U}{R} was spent.)