It was the night of James Potter's 18th birthday. He, Sirius, Lupin and Peter were out celebrating. Peter had a fake ID as he was the youngest.
"Hey, Siri, Remmie?" slurred James. "Le's play truthor dare," Sirius was the most sober as he had put a spell on himself that was like super-concentrated caffeine, so the drink wasn't as strong. "Okay, James i dare you too... Turn into a stag." James wrinkled his nose and half-fell over. "Tha's easy," but he did it anyway.
Within seconds, a fully-grown stag was tottering in front of them. Peter stumbled up to them, pushing through the crowds of people outside.
"What... Hap'end ta James?" Peter's mouth struggled to make the words.
"Sirius dared him," Lupin replied, leaning on Sirius. Peter nodded even though he obviously had no clue what was going on.
Suddenly, James the drunk deer, decided he wanted to go for a run.
A Muggle teenager, who had also just turned 18 walked out of a bar with her friends and saw a fully grown stag, running chased by two men, in varying stages of drunkness, the stag also looked pretty drunk. They ran in front of her, then a few minutes later, as she's begun to think she's imagined it, another young man puffed past her, staggering and weaving.
It was the first and last time she ever drank.