Just like a player "Loot 1" action, the ooze will pick up all coins on its hex or adjacent hexes. These coins are lost - the ooze doesn't drop them again when it dies (just the normal one coin). The ooze, however, cannot loot treasure tiles. Also keep in mind that this action does not influence how the ooze moves. Since there is no attack written on the card, it focuses and moves as if it had a normal melee attack.