Destroy the Blue Tektites on this ledge, and face off against the Like Like. Don't get too close to it because it will suck you into its giant mouth and steal your valuables. A good way to defeat the Like Like is to keep your distance and simply toss a couple Bombs at it. If the creature steals your items, you'll get them back once it's defeated. When the Like Like is gone, use the Hookshot to grab onto the ceiling and cross over the spikes. Walk through the door.