Hungramps has the appearance of an elderly man, with a white mustache and large white eyebrows above closed eyes. He has a blue tongue and a single prominent tooth in his jaw. His most notable feature is his cone-shaped head, with the vertex being the top of his head. He wears a gray kimono, a blue obi and one-toothed geta sandals with white tabi. He is usually seen with a small drool on the left side of his mouth and his right index finger on the right side.
In the anime, Hungramps is an old man. He appears to be lost in thought most of the time. He falls asleep quickly and wakes up shortly after.
A running gag in most of his later appearances is his notorious hunger and craving for food-themed Yo-kai like Wotchagot and Pride Shrimp, or at least animal Yo-kai who could serve as food, like Spenp. Once he senses the presence of Yo-kai like these, and/or at lunch time, he approaches them and proceeds to eat them. Due to this, he is infamously known as one of the terrifying Yo-kai from the Eating clan.
Hungramps has a seemingly bottomless appetite, and thus possesses the ability to make people so hungry they might overeat when inspirited.
Back when Hungramps was alive he had a granddaughter named Sarah who he loves very much. When she grew she hung out with her grandpa less often. When Hungramps died he turned into a Yo-kai and waited to see his granddaughter's face. In episode 4 of the anime he saw Sarah again as a teenager, and she stated that she did want to hang out with him. In EP059, she promised him that she would study hard in order to become a doctor to cure his illness. Seconds before they linked pinkies, Hungramps died. After his death, Sarah continued her studies in order to fulfill that very promise.
Hungramps formed a friendship with Grubsnitch, since both Yo-kai have insatiable hunger, which leads to them seeking for food-themed Yo-kai and devouring them. In the White and Red Song Battle, they even form a unit named "Tabemono Gakari" and compete on behalf of the Red team.
Hungramps is infamous among food Yo-kai like Wotchagot and Pride Shrimp for them continuously being victims of his hunger. In EP088, he even turns out to be the culprit of the "food Yo-kai murders", which caused his victims to lose their souls. Oddly enough, they seem to forgive him and on top of that they invite him to go out to eat. His hunger does not seem to be limited to normal food Yo-kai, as in EP103 goes to the mall during the New Year in order to catch the recently spawned Spenp and eat him.
Yo-kai Watch animation series
Hungramps appears in EP004, Inspiritng a convenience store which Katie Forester passed by. His power makes her and others want to stop at the store and buy food. When she tells Nathan Adams about her craving, Nate accidentally insults her by saying she was getting fat. Nate and Whisper then go to the convenience store to investigate, where they find Hungramps. Hungramps tells them that he has a reason for haunting the store, but he doesn't tell them, mainly because he then decided to nap.
Nate then calls Tattletell to possess him, though there was a slight delay when she and Hungramps had a bit of tea together. Then he reveals that he went to the store with his granddaughter Sarah when he was alive and she was a toddler. They really loved each other, but they grew apart, and he eventually passed away. He started to haunt the store after he died, with his hoping to meet her again being the reason why he became a Yo-kai. He had to draw in everyone because he couldn't quite remember her face since he became a Yo-kai. Whisper and Nate manage to convince Hungramps that he shouldn't cause trouble for others. However, just as he was about to leave, two high school students walk by, one of them holding the same keychain Sarah had, and she discusses the relationship she had with her grandmother. Moved to tears, Hungramps then gives Nate his medal in thanks.
In EP014, Nate calls Hungramps to stop Dazzabel from Inspiriting his mother, since he has a poor sense of fashion. Unfortunately, Dazzabel Inspirits him, making dress up like a surfer, including the surfboard and all else.
In EP023, Nate summons Hungramps to counter Grubsnitch. The two Yo-Kai wrestle for control over Lily Adams, causing her to waver between snitching little bites and eating a full meal. Hungramps ends up causing Lily to become so hungry she starts devouring the meal, prompting Grubsnitch to surrender.
In EP027, Hungramps was seen in Yo-kai-lifornia where he is among the Yo-kai standing in line awaiting the release of the Yo-kai Watch Model Zero. Walkappa told Hungramps that there must be a party that attracted the Yo-kai.
Hungramps' backstory is further explored in EP059, after Nate summons him in order to convince Master Oden with a heartwarming tale. Hungramps revealed that after he became gravely ill, his granddaughter promised to study hard and become a doctor so she could cure him. As he raised his finger to meet hers in a pinky promise, he tragically died right before their fingers could meet. Years later, he learned that his granddaughter successfully entered a prestigious university and continues to work hard in present day.