The story
From lol + cow, suggesting somebody who can be "milked for laughs", similarly to the term cash cow.
Etymology from Wiktionary, CC BY-SA 4.0.
lolcow
Today it means: A person whose eccentric or foolish behaviour can be exploited to entertain onlookers, causing them amusement, revulsion, or other emotions manipulated and harvested by engagement farmers. Full definition →