Shell Shield is a common Instant card from Zendikar Rising (ZNR), collector number 79. Current market price: $0.10 (foil $0.35), TCGplayer market prices via Scryfall.
Kicker {1} (You may pay an additional {1} as you cast this spell.) Target creature you control gets +0/+3 until end of turn. If this spell was kicked, that creature also gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)