Nook grass is an alchemy ingredient from Dragon Quest VIII that serves as a higher tier of fiery ingredient above the Red mould. It is equivalent to using two red mould when used to transmute Super spicy cheese. It can also be used to make the ever powerful Crimson robe.
Nook grass cannot be bought and can only be gotten as a gift from NPCs. It is first given to the party by Marta for Marek, and then eventually Marek will be the one to dispense the rare herb. It sells for 600g.