What do i do for the move maniac on Pokemon LeafGreen?

Answer 1

The move tutor lives in Two Island and he can teach any move your Pokemon has ever learned before, as long as it pertains to its species. To be able to get one of your Pokemon tutored you need to bring him two TINYMUSHROOMs.

There are two ways of getting these rare mushrooms.

If you found the TM 46 THIEF teach it to one of your Pokemon and head over to either Mount Moon or Cerulean Cave and hunt for Paras and Parasect. They hold TINYMUSHROOM and BIGMUSHROOM; one of every three times or so. Use the move thief on them and your Pokemon should be able to catch their mushrooms.

If you have NO WAY to get THIEF, you can CATCH Paras and Parasects in PokeBalls and take their mushrooms then release them. Or keep them as spares when you need to trade Pokemon.

There are some Pokemon who are born with THIEF capabilities, you'd need to trade with Sapphire, Ruby or Emerald to get them, they are:

Poochyena

Lombre

Kecleon