~Quick Rule about this particular topic: Every post must have something unlucky/bad/unfortunate/fail happen to your character.~
Serenity was climbing the positively dangerous Climbing Wall of Camp Half-Blood, dodging lava flows, rocks and other assorted goodies. Of course, for a demigod, none of this was particularly dangerous...if you were paying attention. And since Serenity was thinking about a lot of things, like her low supply of nectar, her recent defeats in the Arena, stuff like that. Consequentially, her left hand was hit by a large rock, causing her to lose her grip and since her right hand couldn't sustain her body weight without completely exhausting her body, so she just dropped.
Rather unfortunately, she had failed to realise there were people below her, so she shouted out "LOOK OUT BELOOOO-" before landing on someone, and in a rather awkward position too.
~Note:She wasn't that high on the Wall.~