An opponent controls a creature with toughness equal to one.
Steps
Activate Mana Vault by tapping it, adding ({C} magic symbol) ({C} magic symbol) ({C} magic symbol) .
Activate Acorn Catapult by paying ({1} magic symbol) and tapping it, targeting a creature an opponent controls with toughness equal to one.
Holding priority, activate Krark-Clan Ironworks twice by sacrificing Mana Vault and Acorn Catapult, adding ({C} magic symbol) ({C} magic symbol) ({C} magic symbol) ({C} magic symbol) .
Resolve the Acorn Catapult ability, dealing 1 damage to the creature, causing it to die due to having zero toughness, and causing its controller to create a 1/1 Squirrel creature token.
When the opponent's creature dies, Glissa triggers twice, returning Acorn Catapult and Mana Vault from your graveyard to your hand.
Cast Acorn Catapult and Mana Vault by paying ({5} magic symbol) .