The sick bomb is a weapon that appears in Dying Light , the way to receive the Blueprints as follows; go to the roof of The Tower where the Crane is, look at the checkers board located on the other side of the building parallel with the entrance door, make a move and then proceed back down The Tower and leave the confines of the safe zone. You simply have to walk beyond the perimeter when the message 'leaving the safe zone' appears. Now head up again, enduring the load time once more and you can make another move.
Proceed to do this for a total of 5 times. After the fifth time, the white player (you) have won the game. Leave the confines for the final time and when you return to the board the blueprints will be sitting on top of it.
The SiCK bomb causes all affected infected to have explosive diarrhea which can be seen erupting from their rectums. Lesser infected, such as biters and virals, may even fly around like balloons that are let loose after inflation, although air isn't what is being expelled. (This is a serious and accurate description, NOT A JOKE!)