Use Rock Crabs for Balance! (イワガメでバランスとろう！, Iwagame de Baransu Torou!, lit. Catch the Rock Turtle Balance!) is an event in Tomba! 2: The Evil Swine Return.
Obtain the Rock Crab and bring it to the Treasure House in the Deep Forest.
To trigger the event, you can either go to the far left area of the Deep Forest or go to the Treasure House. Once the event is triggered (if you did not trigger the event by obtaining the Rock Crab), climb up the Seesaws and go into the Treasure House.
You will need to clear the Device Guards the Treasure! event to get into the room. Talk to the Donglin in the Treasure House and after the dialogue the event will end.