Just a quick one shot that came to me before. Set during Harry Potter and The Order of The Phoneix in the time before Harry came to Grimmauld Place.
Ron rolled over in his sleep with a grunt. As he did so, he felt something incredibly light skim the top of his head, and then something scuttled across his cheek. He froze, his eyes snapping open. Heart beating like the wings of a quivering snitch he slapped a hand against his face and felt the spindly, slightly furry legs of a spider. Screaming he jumped up and, upon becoming entangled in his bed sheets, rolled to the floor with a thump.
The bedroom door flew open and light from the landing poured inside. In the doorway Ron could see the illuminated figure of Hermione. Wand raised in front of her, she ran in to the room. "Ron! What is it?" She cried.
"Sp-spider," Ron croaked, trembling on the floor.
Hermione stopped in her tracks. "Are you being serious?" She muttered, then, pointing her wand at the floor, she said, "Lumos!"
The tip of her wand ignited just in time to catch the fairly average sized spider attempt to crawl away under the bed. Hermione reached down and deftly snatched it in between her thumb and forefinger. Sighing and muttering to herself, she crossed the room and opened up the window, carefully dropping the spider out of it.
"Thanks," Ron said bashfully, feeling rather embarassed as he struggled out of the confines of his bedsheet and stood up. He ran a hand awkwardly through his shock of red hair.
"Honestly, Ronald. A spider?" Hermione tutted, folding her arms.
"They have eight legs, in case you didn't notice!" Ron snapped defensively, "And some a poisonous."
"I doubt a common house spider would cause much harm, Ron," Hermione said.
"Yeah, well, you never know what you're going to find in this bloody place..." Ron mumbled.
"Good night, Ronald," Hermione sighed, shaking her head as she left the room.
"Yeah... night," Ron mumbled. He looked suspiciously around the room again before closing the door and climbing back in to bed.