Identify animation (80's) group of men encounter a witch in a cave

Question

• What is it?: An animated movie (or less-likely an episode of a series).
• Tell us what it isn't: It is not Fire & Ice, Wizards.
• Tell us what made it memorable: A group of men encounter a witch in a cave. There is some talking and they appear afraid. A young man/boy attacks the witch, but she puts her nails in his arm/back and the boy begins to age rapidly till the point of death. It was a pretty graphic (violent) scene.
• When did you see this film?: Late 80's, early 90's.
• How old was it?: Unsure, it feels like from the 80's (Bakshi-like)
• Was it part of a series?: Probably not (only recall that single scene).
• What details can I recall?: Animation was a bit crude, not too many details. Most men looked like in their early 30's, muscled, Caucasian, simple brown clothing (pre-middle ages). The witch was a typical old woman smaller then the men.
• Other details: Probably drawn using using rotoscoping. Saw it on TV (in The Netherlands). Could be based on Greek/Norse mythology (guessing).

Answer 1

It is Valhalla (1986), a Danish animation movie. The scene starts approximately 55 minutes into the movie. Found it by browsing lists of animated movies from the 80's on Wikipedia and checking possible matches. It didn't help that I misremembered some details. The witch is not attacked by the boy, but engages in a dance/wrestling match with Thor. The boy is the only one who's able to see what happens for real (the witch is Age itself) through a mirror and frantically tries to warn Thor. The scene is still pretty scary for kids, but the movie is far less sinister than I imagined, pretty lighthearted and quite watchable.

Answer 2

It might be Metamorphoses (1978)/Winds of Change (1979).