The Justin ingredient is a secret item players can find in Roblox Wacky Wizards. It's a fun little Easter egg that, once found, can brew a potion that turns the player into Lankybox, a popular YouTube content creator. All players can find the Justin rock ingredient by looking in the green shrubs, within the cave entrance toward Oz the Wizard.
Oz the Wizard is located in the secret cave with the green shrubs blocking the entrance. For reference in the overworld, this specific green shrub cave is located near the tallest tree where the Bird ingredient is found, the ramp, and the long concrete runway.
When you've found the cave entrance, you don't need to progress into the cave. The Justin rock ingredient is located at this entrance, hidden within the green shrub on the left side of the entrance. If you step into the green shrub and remain inside of the shrub, look to the left of the entrance and you'll see a small rock smiling back at you.
And that's all there is to it! Pick up the Justin rock ingredient and bring it back to your cauldron. Placing the Justin ingredient inside the cauldron will brew a Lanky potion. And once consumed, you will transform into Lankybox, the popular YouTube content creator!
Since the Justin rock ingredient is a secret item, you can't place it on your table to keep forever. Instead, you will have to return to the green shrub cave entrance every time you want to look like Lankybox.