story identification - Animation movie (80's-90's) with brain-sucking insects

I'm looking for a movie I've seen as a kid, the details are foggy and sparse but I'll try my best following the guide:

• What is it?: An animated movie.


• Tell us what it isn't: It is not Nausicaä of the Valley of the Wind.


• Tell us what made it memorable: A planet where some brain-sucking insect-like aliens live, also an old bald man lives on the same planet.



• When did you see this film?: Late 80's, early 90's.


• How old was it?: If I've seen the movie on TV in Spain, is a pretty safe bet that it will be at least 5 years old.


• Was it part of a series?: I don't think so.


• Plot: No clue, sorry.


• What language was it in?: The movie was dubbed to Spanish (Spain).

No detail is too insignificant

• What details can I recall?:
  
  
  
  
  • Sci-Fi story with one character being an old bald man living on a planet where some insect-ish aliens can open your skull and suck your brain.
  
  
  • Habitat of those insect-ish foes was depicted in light blue colors, I kinda remember giant mushrooms as well.
  
  
  • A young boy befriends the old baldie, the boy came to the planet with some adults.
  
  
  
  


• Other details I'm not completely sure (maybe my mind is filling the gaps):
  
  
  
  • I think that the movie was drawn using rotoscoping, not 100% sure though.
  
  
  • I cannot remember which year I've seen the movie, but it should be late 80's or early 90's.
  
  
  • I'm pretty sure that I've seen the movie in Spanish TV (not rented videotape).
  
  
  
  • Somehow the young boy was the young version of the old baldie (time travel?).
  
  
  • The old man lives in a wood house near the brain-sucking insect habitat, as many old man does he spend his time on the porch.
  
  
  
  

Try to offer unique details

As anyone would expect from this kind of movie, there's a scene where the alien insects attack a group of people trying to suck their brains. A young boy was with those adults and survived with injuries in his head.

The old bald man have some surgery in his head due to an attack he suffered years before.

Answer

Using the web page What is my Movie? and using the keywords animation+movie+insect+brains I scrolled down and look at something that could resemble that movie.

This is Time Masters (1982).

This is the trailer: