War Barge is a special Artifact card from Time Spiral Timeshifted (TSB), collector number 116. Current market price: $0.24 (foil $0.97), TCGplayer market prices via Scryfall.
{3}: Target creature gains islandwalk until end of turn. When this artifact leaves the battlefield this turn, destroy that creature. A creature destroyed this way can't be regenerated. (A creature with islandwalk can't be blocked as long as defending player controls an Island.)