Mask of the Pact Bearer

Mask of the Pact Bearer
Wondrous item, uncommon (requires attunement by a warlock)

This mask appears like a normal wooden mask before you attune to it. When you attune to this mask, your otherworldly patron's presence over you magically reshapes it to represent the visage of your patron. While you wear this mask, you can cast one spell from your patron's expanded spell list without expending a spell slot. The spell must be of a level equal to or less than your warlock spell slot level. A spell cast in this way is always cast at its lowest level, regardless of your normal warlock spell slot level. Once the mask has been used in this way, it can't be used again until the following dawn.

They used to say I was faking it, and that I didn't really have a guardian watching over me. Now they know that not only am I watched over, but that they are being watched as well.