If a cultist has appeased Perfect Memento enough times, they will mutate and take on a much more terrifying form as a result. It is unknown to what actually happens to these mutated cultists, but there is a theory that they eventually become a Doomsday puppet.

The Doomsday puppet appears a s smaller and more weaker form of Perfect memento, and seems to meander around aimlessly, killing any poor schmuck that might cross its path. It is also surrounded by what appear to be higher ranking Doomsday Followers that wield sickles instead of daggers.

The Doomsday Puppet has what appears to be a flame on its chest, and its fed the souls of the dead, which once it acumulates enough, it enrages and... well, let's hope you're a good runner.