Streambed Aquitects is a common Creature — Merfolk Scout card from Lorwyn (LRW), collector number 91. Current market price: $0.16 (foil $0.84), TCGplayer market prices via Scryfall.
{T}: Target Merfolk creature gets +1/+1 and gains islandwalk until end of turn. (It can't be blocked as long as defending player controls an Island.) {T}: Target land becomes an Island until end of turn.