Sir Slicer makes his only appearance in the episode, "Blood Under the Skin." In the episode, Sir Slicer antagonizes Finn, telling him that he is weak because he doesn't have full body armor. Sir Slicer rides a pink horse with a white mane and tail. His appearance is always preceded by a group of flying crows against his silhouette, with a rushing background and leaves blowing in the wind. He follows Finn and mocks him after the Swamp of Embarrassment for having "crimson cheeks." Sir Slicer also hires a lute player to make fun of Finn after the Red-faced Monster tries to get him to nurse. He last appears after Jake gets the Armor of Zeldron, still making fun of Finn and Jake despite their success. However, in the end his armor proves too heavy for him to move when dismounted, and he finds himself on the receiving end of embarrassment and laughter.
See Sir Slicer/Quotes
- Sir Slicer made an appearance in Sound Castle 2. It takes three hits (one of each color) to take him down.
- Slicer's voice actor, Peter Stormare, is also known for lending his voice to several video game characters such as Mattias Nilsson; a Swedish mercenary from the video game titles Mercenaries and Mercenaries 2: World in Flames.
- Sir Slicer is a parody of Baron de Ghost (original name: Danshaku), the villain in the 1981 film The Fantastic Adventures of Unico based on the manga characters of Osamu Tezuka.
- Sir Slicer's horse seems to be very strong; it can carry the weight of Sir Slicer's armor.