How do you get past the octopus in majora's mask?

Answer 1

In Jabu-Jabu's belly the large tentacles that trace from ceiling to ground, if those are the ones you are talking about you have to go to a room with three hallways branching off from the entrance. Please note that you have to have the boomerang to do this, you go into one of the rooms, and there will be a large tentacle hanging from the ceiling, 'Z' target and fire your boomerang at the point Navi is targeted at, after three hits the tentacle is done, and so is one of the larger ones blocking the door. Rinse and repeat for the rest.

Answer 2

you have to follow the monkeys to find a witch in the woods and then do as she says. Eventually you will get to use the boat in the swamp, with the boat, you can pass the octopus

Answer 3

throw a boomerang at them, or run away. i think the slingshot stuns them ( dont quote me on that)