(Reposting because I reversed the Z and X buttons in the instructions before... shame on me :v)
Instructions: Z key to jump. Jump over the Fungi a certain number of times to stun them. While they are stunned, press X to give them a Biscoin (if you have at least one) and you will make him Chawie's friend! After that, press up to talk to them.
(and thanks to the people giving their support!)