They just arrested Sirius cuz he's Black.
Free the marauders!
Not sure about the reference, im thinking Harry Potter's father's Patronus
@abelgray, James Potter was a stag in his animagus form
@abelgray, Sirius Black could turn into a big dog at will, James Potter could turn into a stag at will. They had many an adventure. Seems this one got them involved with the muggle police.
@hannabanana, ah, thank you
@TheHashTagger, it's was James' stag night before his wedding. Things got ruff. It was only a kiss.