Thinking Cap

Wondrous Item, uncommon (requires attunement)

Your Intelligence and Wisdom scores are 15 and your Charisma is reduced by 2 while you wear this leather cap. It has no effect on your Intelligence if your Intelligence is 15 or higher without it, and it has no effect on your Wisdom if your Wisdom is 15 or higher without it.

You also gain advantage on all Intelligence and Wisdom ability checks, but you are so focused on your thoughts that you have disadvantage on all Dexterity and Strength ability checks.