Find the severed head gunsMISSABLE
This trophy is for finding one of the Easter Eggs in the game, two guns in the shape of severed heads which are found in Act 3, in the final level of the game, Of Wulfs and Demons . When you enter the boss room, ignore the bosses and head up the stairs that circle the perimeter of the room until you reach the top. From there you need to climb up another level by using the tiny ledges on the straight pillars (the thinner, square-shaped ones, not the round ones) around the room. Shoot down the cages that are hanging at the high ceiling at the very top. This gun is a little glitchy and instead of showing on the floor, you'll see it shining in the wall (see my video below to see what it looks like). All you have to do is walk near it and the trophy will pop. (As a side note, you can equip and use these like any other gun weapon.)
Note: You have to get it before you kill both bosses, as once you kill the last one, the game ends and you can't go back, you'll need to restart the boss fight.
Here is a video showing its location and how to get it: