With the introduction of the lunar grotto we knew that the moon influence can affect mushrooms and mushtrees.
What if we could make something to mutate toadstood like how we poison him with his own poison with a canary. Making a similar fight but with differences like spores when chopping his mushtrees or narcotic clouds (a use for the new mushroom dish) for example.
In that way we can get a recipe for a new mushcap that spawns moonspores that deals damage (maybe when we recieve damage wearing it the player spawn a bunch of moonspores). Also we could get some kind of recipe like the napsack to sleep enemies using moonshrooms (will actually have more sense that the napsack).