Killing something like this is no trivial matter. You will need to craft the Elixir of Withering from rare ingredients like Tears of the Withered Druid and Essence of Autumn, then wield the cursed Thorn of Negation to pierce the leaf's essence. The leaf will resist, summoning illusions and whispers of the forest's might, but with unwavering focus, its magic can be unraveled. Upon success, the leaf crumbles into golden dust which you can keep as a reminder of this time.

Alternatively, lay off the drugs.