Ron didn't know who cast the Jelly Legs Curse on him as he was trying to catch up to Hermione. He hadn't the time to look back as he hit the ground, trying his best to lessen the impact. That didn't stop his head from smacking into the ground painfully, though. Ron was just glad there was no blood.
It took him a few precious moments to fumble for his wand, and casting the countercurse was a bit more difficult without Hermione around. And had taken far more tries than Ron would like to admit, but Hermione had already disappeared down the corridor and Ron doubted he would be able to follow her now.
Sighing, Ron realised that he would just have to wait until she returned to the common room to talk to her. Ron hadn't thought Lavender would go so far to get together with him again. He had honestly thought that she had been over the phase, but apparently he had been wrong.
He had to apologise to the witch, and set things right.
Even if he doubted she would forgive him this time.
Written for October Event: Bingo – Jelly Legs Curse
Written for Ultimate Chocolate Frog Club: Flavius Belby [Incorporate an unprovoked attack]