The power to be a mockery of someone or something.
The user of this power is or can transform others into mockeries - grotesque, exaggerated, monstrous versions of themselves.
While most mockeries embody negative qualities even good qualities can be dangerous when taken to their logical conclusion, for example a moral person can be turned into a fanatical zealot who murders people for not being good enough. Depending on the circumstances a mockery can be either a person who committed a crime or the victims of the crime and evil who have returned to punish them.
Cenobites (Hellraiser) were humans that opened the Lament Configuration, being tortured to the point of becoming caricatures of their human selves, sometimes even reflecting what they were in life.
Demons (Supernatural) were once normal humans that were sent to Hell for their wickedness in life, becoming tortured to the point where their humanity became stripped away, becoming monstrous spirits out to spread suffering and misery wherever they go.
Cluster Gems (Steven Universe) are shattered Gem-shards forcibly fused together, creating horrifying grotesqueries out of the remnants of dead Gems.
Slashers (Hack/Slash) are people with Black Ambrosia in their bodies who died, having come back to life as twisted, murderous caricatures of their former selves with a mindless compulsion to kill.
After the Presence (DC Comics/Vertigo) was "killed" with the sword of Azrael, he went into a comatosed state where he was reborn...
...as a malformed mockery of himself.
Joseph Bertrand III (Infamous 2), was a hypocritical preacher who uses his position to encourage hatred toward conduits in humans...
...becomes a literal monster...
...who transforms others into conduit monsters.
The Monsters (Silent Hill) found within Silent Hill are commonly manifestations of the aspects of those trapped within it or the ones in control of the town's evil.