I read this a couple years back, best as I can recall, enjoyed it and wanted to rec it over on TVTropes, but I can't bring title or author to mind now: a short Weasley-oriented pre-Philosopher's Stone story focused on one of the twins, who seems not to be a twin at all, though still a prankster. The story ends with him essentially creating the other twin as a prank on his family.
Sound familiar?
-- Bob
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Then the horns kicked in...
...and my shoes began to squeak.
Sound familiar?
-- Bob
---------
Then the horns kicked in...
...and my shoes began to squeak.