Slicer a major character in Pet Story and the central antagonist of the story. He serves as the main antagonist of the Classic Ending, a reformed character in the Lab Ending, and a minor character in all other endings.
Slicer during the beginning of the story and the Classic Ending has shown to be extremely grumpy and even mentioned by Susie to also be aggressive during his last week with them. The Classic Ending also gives an example of his aggression where he attacked the players in the Deadly Shelter, although as revealed in the Lab Ending, this attack was likely forced by Dr. Flea against the players.
After the Lab Ending though, Slicer reforms after being mind controlled under his cyborg persona, where he becomes calmer and being a gentle giant on the others. He was also afraid he wouldn't be adopted due to his aggressive personality, although this was proven wrong seconds later.
Slicer is a black Doberman with brown patches on his jaw, inside his ears and on his paws, he also has red eyes in an angry expression.
In the Lab Ending, he gains a robotic armor that covers the right half of his face, his snout, jaw, the front half of his torso, arms, paws, and his tail, and a yellow glow comes out from inside his ear and from the eye of the robotic armor (also his name is changed to Roboslicer when this happens)
When the players are first spawned in the shelter, Slicer is seen sitting in a cage disagreeing with Canela on how the humans treat the animals in the shelter. When Grannie arrives at the shelter, Susie allows her to adopt any pet(s) she likes. Of course, she adopts all the players and Canela, leaving Slicer behind, as Susie mention of it being his last week at the location. Offscreen, Slicer is released from the building and put into the Deadly Shelter. Afterwards when the players go to the Deadly Shelter, he is seen hanging Canela in a cage near an incinerator. When the players asked if he should be dead, he agrees but due to the players despising him explained how Animal Control adopted him to do the dirty work and engages a battle with the players. Despite his best efforts to kill of the players, he is defeated himself and thrown into the incinerator to a burning demise.
If the players choose the Lab Ending, Slicer is seen guarding the battle area that the players out fight him in before Dr. Flea takes notice of this. Afterwards, he assigns Slicer to be turned into a cyborg in his laboratory. Slicer is then seen as his cyborg alter-ego, Roboslicer. From here the players must fight Roboslicer, in order to free Slicer of Flea's wrath. After being defeated he turns back to normal, albert heavily injured. Afterwards, he is taken back to the adoption center where Susie, heals him. Slicer then tells the others to go on a manhunt for Dr. Flea still as the latter managed to getaway and is still on the run turning pets into cyborgs. Afterwards, Susie surprises him with him getting adopted by Doug from Airplane 4.
If the players instead choose the Christmas route, the Sewer route, or the Zoo route, Slicer ends with the same fate as he is taken to the Deadly Shelter, but does not battle the players due to their absence as they do not enter the shelter in the first place. From here, his fate remains unknown at the shelter, although due to what is seen to him in the Lab Ending, it is likely that Dr. Flea could have turned him into Roboslicer.
If the player beats the story ten times, then they will unlock Slicer as a skin which can activate hardmode if playing as him. From here, Slicer can be used to gain exclusive skins (specifically those that are the end boss of an ending) for different endings if the player manage to beat a game with him. If they beat the story with him on the Classic Ending, they will unlock Neon Slicer, which is simply a reskin of him but just with neon colors. If the players beat the Christmas Ending, they will unlock the Polo skin. Second, if the player beat the Lab Ending with him, then they will unlock Roboslicer as a skin. Third, if the player beats the Sewer Ending with him, they will unlock the Croc skin. Lastly, if the player beats the Zoo Ending with him, they will unlock the Claw skin.
- Aggressive Charge - Slicer will charge at the players taking a few seconds to charge his attack, they can easily be avoided as a series of dashed lines can be seen where he is going to attack next. Each charge deals 10 damage to the player if hit on contact. During each phase, Slicer will get faster and thus a bit more unpredictable.
- Howl of Doom - Slicer will move to the center of the stage and proceeds to lock and aim at the player. Afterwards he will howl three shockwaves and proceeds to howl ten times before moving on to his third attack. During each phase the howls get faster each time
- Flamenco Twirl - Slicer will aim at the player at a slow speed while constantly twirling his body against them. When performing the twirl, Slicer will howl a shockwave at the players while he is doing his attack. During each phase, his twirls get faster and that he howls more shockwaves each time.
- Shock Bombs - A bunch of bombs will follow the players with a red circle on the bottom of the bomb, indicating how big the shockwave to going to be when it explodes.
- Shocking Stroll - When not using any attacks, Slicer will simply walk around following any players very slowly and would bite a player on contact if a player touches him.
- Electrical Twirl - Alike his Flamenco Twirl, this attack is basically the same although one difference is that he uses his howl shockwaves more frequently.
- Antenna Zappers - The antennas on the corners will attempt to zap the players on phase 3. Just like the shock bombs, the zappers have an indication where they are going to zap.