As social media lit up with talk of the U.S. presidential election outcome, some users responded to Donald Trump's victory with cynicism and humour, using the hashtag "Trumpocalypse" to predict doom and gloom for the future of the country.

Many compared Trump to pop culture villains who became president in works of fiction, including "Back to the Future" bad guy Biff Tannen and Lex Luthor, Superman's arch-nemesis. Biff became a casino mogul and president in "Back to the Future Part II," while Lex Luthor used his real estate business to manipulate his way into winning the presidency, in a Superman comic book storyline from 2003.

"Lex Luthor is going to be the U.S. president and we don't have Superman," comic writer Bryan Hitch tweeted on Wednesday.

Others pointed out the similarities between Trump, a real estate mogul and former casino owner, and Biff Tannen, the villain in "Back to the Future."

Screenwriter Bob Gale, who penned the script for "Back to the Future Part II," has publicly stated that the character of Biff was based on Donald Trump.  "We thought about it when we made the movie," he told The Daily Beast in 2015.

But "Back to the Future" and comics weren't the only works of fiction to suggest a Trump-like candidate might one day take the White House. "The Simpsons" also predicted Trump's presidency, in a flash-forward episode first broadcast in 2000. In the episode, President Lisa Simpson says she's inherited a budget crisis from her predecessor in office, Donald Trump.

Amid all the Biff, Luthor and "Simpsons" tweets, others predicted the "Trumpocalypse."

Also trending on Wednesday was the hashtag "ImStillWithHer," a modification to Hillary Clinton's "I'm with her" campaign slogan.

But amid the outcry over Trump's victory, plenty of others were celebrating.