That same night...
Harry stood up, the memory of Snape's behavior making him feel very anxious. He pressed his ear to the door. He was pretty sure Ginny had left but didn't want to take the chance. He took the Marauder's Map out of his trunk and checked it carefully. Ginny wasn't even on the same floor. He sighed in relief. Hermione and Seamus were the only two in the tower. Harry grabbed his invisibility cloak and walked down to the common room. At first he didn't see anyone in there and gave a shrug, they must've left when I was putting the map away. He'd almost made it to the portrait when he heard a moan and a lot of shifting. He turned back, his eyes popping out of his head when he realized what he'd just walked in on. Seamus Finnegan on top of Hermione. He stood there gaping for a few moments, unable to help himself. When the clothes started coming off he shuddered and left the room in a hurry, barely remembering to throw on his cloak.
He went down to the dungeons. Last year he'd discovered a secret passageway that opened up inside a tree in front of Black Lake. He used it now. He desperately needed to be submerged in water. Harry just hoped that the spell to mask his scent and the invisibility cloak would be enough to hide him from whatever beasties awaited him outside.
Once at the lake he stripped down to his boxers and dove in. The relief he felt was immediate. It was wonderful. Somehow, this was different than his experience in fourth year during the Triwizard Tournament. Then it had just been something he needed to do. Now it was like freedom. It gave him the same euphoric feeling as flying and it was marvelous. What made it even better was that this time he didn't need to go up for air or swallow gillyweed or use a charm to be able to breathe. He figured it was just whatever powers that came with being a water sprite that automatically made it breathable for him. Though he was enjoying himself too much to care or give it much thought.
He also wasn't being attacked by Grindylows, in fact they seemed to avoid him. Some of the mermen swam after him, but they were easy enough to elude. He discovered that he could make the water solidify to form a wall or create bubbles to act as a kind of mist. The Giant Squid swatted at him playfully, but otherwise left him alone.
Harry lost track of time, swimming for hours on end. When he finally poked his head out of the water he was surprised to find that it was nighttime. He swam to shore. Unfortunately, the scent-masking spell had long since worn off. He took one, maybe two steps when he felt himself swept up in a pair of large, hairy arms. His one panicked thought, HAGRID!?! WHERE ARE YOU WHEN I NEED YOU!?!?
He let out a shriek. He felt stupid doing it, but knew that without his wand, his best chance of escaping was to use his voice. It was laced with power and sure enough he was dropped almost immediately. He looked up to find Bane, the centaur he'd met in his first year, cringing with his hands over his ears. Behind him was one of the more unusual beings he'd ever seen, coming from a wizard of some six years that was saying a lot. The man had no forehead; instead he had an extra six eyes. He also had four extra arms. Harry gave another shriek to keep them at bay, and watched in a sort of horrified fascination as the man dropped to the ground in pain: morphing into an acromantula and back again. Huh. He didn't know they could do that.
He was snapped out of his daze by a loud roar coming from the general direction of Hagrid's cabin and ran to his tree, grabbing his clothes and cloak as he went. Once safely ensconced inside, he sat down with a huff. It took him several minutes to calm his heart and breathing. Geez, Volemort was dead and he still couldn't go anywhere without being attacked by something. The only difference was previously they'd all wanted to kill him and now they wanted to possess him and fuck him. Honestly, he didn't know which was worse.
He trudged back to Gryffindor tower. He didn't like staying in the dorm room now that he was the only one in it (Seamus had been disappearing every night, with Hermione, Harry now knew). Still, he didn't have anywhere else to go. He curled up on his bed and went straight to sleep, completely exhausted.