He never saw it coming.
Police say the 30-year-old victim was leaving Ruchi's Mexican Grill in Rosenberg when he was attacked.
Police say the suspect is 18-year-old Alejandro Maldonado.
Officers say he agreed to turn himself in last week but never showed up.
"That knock out game is what we're assuming is what's going on here," said Lt. Chad Pino of the Rosenberg Police Department.
Police say the years old so-called knockout game hasn't been an issue for their city.
Investigators say calling it a game is a bad idea. They call it aggravated assault.
"We hope it's isolated. I mean it's a cowardice act," Pino said.
Other young people in the area agree with police-- this sucker punch is cowardly and no joke.
The victim hits the pavement hard and was rushed to the hospital with serious injuries.
"I've seen the videos before but nothing that malicious," one said.
"It's not going to be funny when you're in prison."
The victim is now back home-- police don't think he and the suspect know each other.
They're hoping Maldonado turns himself in.