TrampleGoblin Rock Sled doesn't untap during your untap step if it attacked during your last turn.Goblin Rock Sled can't attack unless defending player controls a Mountain.
Giant Shark can't attack unless defending player controls an Island.Whenever Giant Shark blocks or becomes blocked by a creature that has been dealt damage this turn, Giant Shark gets +2/+0 and gains trample until end of turn.When you control no Islands, sacrifice Giant Shark.
, : Target attacking creature gets +2/+0 until end of turn. When that creature leaves the battlefield this turn, sacrifice Runesword. If the creature deals damage to a creature this turn, the creature dealt damage can't be regenerated this turn. If a creature dealt damage by the targeted creature would die this turn, exile that creature instead.