Dark Souls 2 publisher Namco is setting you a challenge. Defeat the game's Mirror Knight boss on the Eurogamer Expo showfloor and you'll be eligible for some serious prizes.

The first person to find and best the rock-hard boss will win a Dark Souls 2 Black Armour Edition and PS3 signed by developer FromSoftware, closed beta access, 12 months PlayStation Plus subscription, a Turtle Beach Ear Force PX22 headset plus an exclusive signed T-shirt and A3 poster.

Players will have just 20 minutes with the game to attempt the feat and only three of these prize packs are available, limited to one per day.

But there are runner-up prizes too - get to the Dark Souls 2 stand and defeat the Mirror Knight later than someone else that day and you'll still get a T-Shirt.

And everyone who plays the game will get the A3 poster - whether you find the Mirror Knight or not (while stocks last).

As you may be aware, Eurogamer Expo is due to take place this week at Earl's Court in London. Tickets are now sold out, but you'll be able to watch all our developer sessions live online.