"Stand and be LIQUIFIED!!!"
- Terror Mask as Rick enters his Mutant form in Splatterhouse (2010)
'thumb|link=File:Berserker_rick.png'Mutant Rick (also known as Berserker Rick or Berserker Mode), is a powerful ability that allows Rick to become an over-muscled monster for a short period of time through the supernatural abilities of the Terror Mask.
In Splatterhouse 3, in order for Rick to both gain and remain in this form, he must go around and collect an certain amount of Eldritch Orbs in order to charge the, "Power bar," and must continue to do so in order to transform into Mutant Rick.
At the very start of the game, the player is given access to all the Mask's powers to give the player a large amount of blood to use later on in the game. After that, the player has to earn the Beserker Rick power and the other abilities of the Terror Mask on their own. Also, Rick cannot use the ability until the end of the Poltergeist boss in Phase Two: The Doll that Bled.
The Necro Meter must have at least three blocks filled in order for the player to use this ability.
In the remake, Rick gains many new advantages whenever he enters his Beserker form. For one, should he be injured at the time, Rick will instantly regain all of his health and will even reconstitute any dismembered limbs he has lost when entering this form also growing bone-like blades from his body and allowing the Mask's spirit to take over temporarily. The Mask can also create portals when enough blood has been spilled by the host. While in Beserker Mode, the entire world is seen through Mask Eye, and Rick has access to all of his current powers as well as all of his upgraded powers and can utilize them to their full extent. All of Ricks attacks deal massive amounts of damage to, allowing Rick to almost effortlessly overpower most of the enemies present in the game; weaker enemies die in one hit, while stronger enemies (enemies who have health bars) will have their energy quickly depleted with only a few small hits.
It's also shown that Rick grows to an even larger size in his Beserker Form in comparison to his, "normal," form in the game.
Unfortunately for the player (not to mention Rick as well), even though the form can be accessed like this during key points in the game, the Beserker Form cannot be activated or deactivated whenever the player chooses so during regular gameplay. Once Rick has transformed, the blood in the Necro Meter will turn white and will proceed to slowly drain; indicating how long Rick has until he transforms back. While the player can exit the form whenever they wish, doing so will cost them a block of the Necro Meter to be emptied. Thus, the Beserker Form should only be used as a last resort; a fail safe when it looks like your about to lose or to quickly deal a large amount of damage to a rather difficult enemy so as to increase your chances of winning.
- From dialogue by the Terror Mask and that the Mask Eye ability is in use, it is believed that the Mask takes temporary control over Rick when he is in this form.
- In Splatterhouse (2010), the opening riff of "Pounding Nails (Into the Lid of Your Coffin)" by The Accusedplays whenever Rick enters his Berserker Form in a loop.
- Rick's "normal," form in Splatterhouse (2010) slightly resembles the Splatterhouse 3 version of Mutant Rick.
- In the remake, the heart that appears on the health meter beats somewhat faster when Rick enters his Beserker Form.
- It should also be mentioned that in the remake, the mask symbol that appears on the Necro Meter will also transform when Rick enters his Beserker Form.