Streets in Cardiff came to a standstill following a new zombie craze set to sweep the rest of the UK.
The cross-city chase game, 2.8 Hours Later, sees players immersed into a film-like story where actors playing the undead are out to get them.
As well as having to outwit and flee the hordes of zombies en-route, participants also get to interact with several characters along the way and avoid getting infected.
Last night, around 500 people in the Welsh capital got in on the act across six locations, including Cardiff City's football stadium, a primary school and an eerily deserted recycling centre over-run with bloodthirsty monsters.
The aim of the game, which takes inspiration from horror films such as Night of the Living Dead and 28 Days Later, is to find clues at mysterious locations in order to reach safety in the asylum zone.
As well as being wary of zombies - in full costume and make-up - players also have to be wary of police and other government authorities trying to quarantine civilians in order to stem the flow of infection.
The aim of the mission is for players to make it back to the asylum, with their tasks completed and without being "infected" with invisible ink.
A UV light is used to scan for ink marks and all players infected were turned in to zombies ahead of the game's afterparty.
The 2.8 Hours Later series, developed by game designers Slingshot, is now in its fifth year and has seen more than 60,000 take part to date.
Simon Evans, who co-founded 2.8 Hours Later with his business partner Simon Johnson, said: "It has been incredible to see players become totally immersed in the narrative, and they seemed to love the adrenaline kick they got from playing the game.
"It's a totally unique activity and a great way to have fun with your friends.
"This is our second year in Cardiff and the game has proved even more popular.
"Tickets sold out so fast that we had to add an extra date."
The event, 2.8 Hours Later, takes place across six other UK cities - London, Edinburgh, Newcastle, Manchester, Glasgow and Sheffield.
For more information visit http://www.2.8hourslater.com