Grumples evolves into Everfore when fused with Ageless Powder.
Grumples resembles a rather elderly woman with wrinkled skin, sunken eyes and only two teeth on her upper mouth. She wears a ragged old cloak, which is patched in some areas and is accompanied by a green sash. She carries a wooden staff with a ghoulish face in the top.
Matching her elderly appearance, she behaves like an old woman, in that she has a lot of trouble hearing Nathan's complaints about her powers and showing signs of senility.
Grumples has the ability to shrivel everything she fires at with a beam from her staff. When used on humans or other Yo-kai, she can age them significantly. However, the effect can be undone with just a splash of water.
Yo-kai Watch animation series
Grumples appears in Yo-kai Grumples when she is revealed to be responsible for the shriveling of Nathan's school paper. Nathan complains, to no avail, since Grumples has severe hearing problems, instead of using her power to shrivel Nathan's clothing and even aging Nathan and Whisper and forcing them to use the sink to dispel her effects. Toiletta appears and puts Grumples and the others into a training regime which works to the point that Grumples rejuvenated into Everfore. The female Yo-kai then gives Nathan her Yo-kai Medal out of gratitude; however, not too long after that, she sneezed and turns back into Grumples, which accidentally starts firing her beams everywhere, which she apologizes for accident firing.
Freed from the Crank-a-kai: "Ah, youth. The key to freedom. Take me with you, won"t you?"
"Grumples" may come from the words grump and wrinkles.
In Spanish, "Arruñona" comes from arruga (wrinkle) and gruñona (grump).
In German, "Dörrte" can translate as dry.
Given that Grumples evolves with the application of face powder, she might be partially inspired by the oshiroi babaa ("face-powder hag"), a ghostly old woman who serves a god of cosmetics, bringing him sake to warm him in the coldest days of winter, and constantly applies face powder on herself because she's ashamed of her aged, wrinkled features.
In Yo-kai Watch 2, Grumples may attack when you agree to escort an old lady, calling you "too trusting" It is un-befriendable when battled.