A game in the Warhammer universe is getting a free weekend. Rats! No, seriously, lots of them.

Warhammer: End Times - Vermintide, a game that is like Left 4 Dead, but with rats, is now a free download on Steam through 10 a.m. PDT on Monday. If you like what you play, you can get it for 40% off the regular price at $17.99 during that time.

If you aren't familiar with this Warhammer game, it is a first-person action adventure set in the city of Ubersreik. As the title suggests, the city has been overrun with vermin, or Skaven. You can play as one of five heroes with up to three other players in co-op.

The game created by Fatshark, and was released last October to fairly positive reviews.