Boko Baba Seed

From Zelda Wiki.org

In The Wind Waker, a Boko Baba Seed is a spoil from Boko Babas. It is kept in the Spoils Bag. If Link gives four of them to Hollo in the Forest Haven, he will prepare a Blue Potion out of the spoils.

This source of the monster plant's magic is said to be most helpful when mixed in the proper quantities.

— Inventory description