VIDEOS:
"Want a beer?"
Before Barney Gumble became Springfield's town drunk, he was once an intelligent, Harvard-bound student before his high school friend Homer Simpson gave him his very first beer on the night before he was due to take his SATs, and the rest is history.
Example of:
Unwitting Instigator of Doom
Darwin's Nightmare
Example of:
Took a Level in Dumbass