Prism is a common knife that was originally obtained by redeeming the code PR1SM. It can now only be obtained through trading since the code has expired.
Notes and Trivia
This knife is only 1 of the 6 youtuber code knives. The others being Corl, Sketchy, Denis, Sub and Alex, not including JD, a very special Legendary knife.
Like every other in game code, this code has expired.