This is true. No one is pulling a cruel joke on you. Right now you can fly from Los Angeles and San Francisco to Europe for $99.
WOW Air offered this deal to East Coasters a while ago, but when the low-cost carrier announced it was going to start flying out of Los Angeles and San Francisco beginning in January 2016, no one thought prices could actually go that low. Flights would be cheap, but not $99. But like a limbo champion, this airline went that low. One-way flights out of LAX and SFO to WOW's hub in Reykjavik, Iceland are being advertised for $99 right now.
Of course, the return ticket will cost you a bit more. But given the distance and the average cost to get from the West Coast to Europe, anything under $400 is almost unbelievable.