Room 9: Frog Fight!
Hit the C button to enter into free-look mode, and glance up at the ceiling here for a disturbing discovery: a giant frog is about to attack you. Be sure you have bomb-arrows equipped for this fight.
The frog will initially launch a barrage of tadpoles at you; keep yourself shielded and abuse your spin attack and normal slashes to finish them off. Afterwards, the frog will probably jump into the air and try to smash you underneath its body. Keep on the run and start rolling when you see its shadow looming large.
After it hits the ground, its tongue will roll out of its mouth. Run over and whack on it with your sword! Do so enough and youíll cause the frog to pause for a second, then belch. Quickly target the tongue again with a bomb arrow, which the frog will swallow. After it explodes inside of its belly, youíll be able to attack the tongue again with your sword. A few rounds of this will net you the Clawshot.
The clawshotís a pretty simple device. When itís equipped, pressing B will allow you to target those little red dots that youíve been finding all over the place. If you fire it at them, youíll let loose a chain that will pull you to the target. (You can also fire it at any vines that you see.) Try it on the multiple targets that are scattered around this room. When youíre ready to move on, fire at the switch on the southern side of the room to open the gate there. The clawshot will make it a little easier for you to return to Room 3, your next goal. Note that it can also rip the shells off of the slug creatures that have been attacking you. (Itís still better to just run past them, though.)
Use the clawshot to make your way up to the chandelier in the center of this room to find a Piece of Heart. You can also make your way to the treasure chest thatís just at the waterline now; it contains 20 rupees.
Other than that, though, make your way to the upper west end of the room and use the clawshot to hit the target where a handle should be located, right above the staircase. Doing so will rotate the stairwell, cause it to become a de facto canal for the water thatís flowing into the room. Follow the water down the stairs and leave via the lower eastern doorway.
Start chaining your way through the room here. The sequence goes: chain to the cog in front of you, drop down to the pillar with the chest on it, chain to the pillar above you with the vines on it, climb around to the flat surface, chain higher up to another pillar, move around to a flat surface, chain to more vines near a door, climb down to the doorway.
Room 11 basically circles Room 10, but only on the uppermost level of it. Hang a right here and shoot down the stalactigamicactite on the ceiling into the geyser below it, then hop aboard! Jump over the wall, then clawshot your way to the door leading east.
You know the drill. Climb the ramp to the top, climb the ladder, jump onto the switch to start the water a-flowiní. The chest behind the water, reachable with the clawshot, contains the Compass for the dungeon. Itíll show plenty of chests in the area, indeed, but feel free to skip them if you wish; most of them will just contain Rupees.
Head back to Room 11. You have to drop down to Room 10 here. If you like, you can try re-tracing the clawshot trail you took up the vines, but itís quicker to simply drop down. If you move onto the westernmost cog, you should find the doorway leading west. Instead of going through the door, though, face north and walk off the stone platform youíre on. You should drop down to the stones below you. Thatíll place you in Room 10. From here, head east by clawshotting the free targets on the cogs that spin around. Youíll have to attach yourself to the westernmost cog, whirl around 180 degrees on the cog, then fall down onto one of the platforms below you. (Donít forget that you can lower yourself on the chain by pressing down on your analog stick; thatíll let you know when youíre precisely on top of one of the platforms.) Connect to the eastern cog, then let yourself be spun around to the eastern side of the room and head through the door there.
Youíll need to do a bit of swimming here. There are kinda-sorta three channels of water in this room, each running north to south. If you dive into the water, youíll find a hole that leads into the middle channel. Swim upwards, and youíll find a platform in the mid-depths of the water with a boulder in the wall. Blow it up, then head through and equip your Iron Boots. Thereís another boulder in the wall underneath where the first one was, so blow that up as well and head through that passageway, then unequip your Iron Boots and head to the surface, where youíll find a door. (Itís quite possible to get yourself turned ass-backwards here by heading through a tunnel; donít do it! Look for the door up in the breathable air; thatís the correct path onward.)
If you went the right way, you should be in a little room with another bubble-worm guy. Kill it, smash the jars, then clawshot the target in the center of the ceiling. Lower yourself down via the analog stick to find the Big Key. With that in tow, return to Room 3.
Piece of Heart?
Oh yes. Before you head into the bossí room (the door to which is located at the base of the stairs in Room 3), you can track down one more Piece of Heart in this dungeon. Begin by heading to the lower western door in Room 3 and pulling down the handle. This will cause the water to flow to the western side of the area.
Head to Room 4 via the lower western door, and youíll note that the bridge in the water has been fully raised. Cross it, then stand on the button amongst all the tiles on the ground. Clawshot your way past the gate before it closes to find your Piece of Heart.
Boss Fight: Morpheel
Head back to Room 3 and unlock the large door. Youíll have to dive into the water at the bottom of the room and swim to it, underneath the pivot that the stairs turn on. You can find a fairy in one of the jars above the hole you drop into. When you do drop down, equip your Iron Boots to fall allllllll the way down to the ocean floor.
Morpheel here is a bit of a weirdo, but he shouldnít cause you too many problems. Keep your Iron Boots on for the first section of the fight, and keep your distance from his tentacles. Creep in slowly, and keep tapping your Z button until you get a lock on the eyeball thatís being shuffled around inside his tentacles. (And how gross is that?) When you have a good lock on it, use your clawshot to pluck it out of the tentacle and pull it towards you, then start whacking at it with your sword. Nasty.
After one go-round of this, Morpheel will complicate things a bit by becoming a bit more aggressive with his tentacle attacks (which will suck you into his mouth and damage you if you get caught) and also releasing a number of smaller bomblets which, when caught up by your clawshot, will be pulled towards you and quickly detonate. These will confuse your z-targeting when youíre trying to nail the eyeball. If you grab them and let them go quickly enough, they usually wonít damage you, though.
After hitting the eyeball twice, Morpheel will reveal its true form: a huge fish that swims around, daring you to catch it. Its weak spot remains the eyeball, but itíll be moved to the upper-back area of its body, behind its head. To catch it, youíll have to detach your Iron Boots and swim up above the beast, wait for it to circle around beneath you, then Z-target the eye and latch onto it with your Clawshot. When you do, and pull yourself in, a few good shakes of the Wiimote will plunge your sword into the eye, Colossus-style. Repeat this process a few times to finish the beast off and earn the third Fused Shadow.