Deadeye Plunderers gets +1/+1 for each artifact you control.
{2}{U}{B}: Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Because damage remains marked on a creature until it’s removed as the turn ends, the damage Deadeye Plunderers takes during combat may become lethal if artifacts you control leave the battlefield later in the turn.