[RPG] Who makes the Int check for an illusion perceived through a familiar’s senses

dnd-5efamiliarsillusionspells

So the Find Familiar spells says that the caster can see and hear through the familiar's eyes and ears. I'm wondering what happens if the familiar encounters an illusion, say a Minor Illusion, when this is happening. Who makes the intelligence check to disbelieve the illusion, the familiar or the caster? Or do they each get a check?

Best Answer

They both make checks if needed

Find familiar indicates the caster sees through the eyes of the familiar, so the caster is observing and hearing possible illusions:

Find Familiar, PHB pg 240.

Additionally, as an action, you can see through your familiar's eyes and hear what it hears until the start of your next turn, gaining the benefits of any special senses that the familiar has.

The familiar continues to see and operate on its own; you can give it telepathic instructions to fly that-a-way, or "That's not real!".

So the familiar too sees, hears, and smells the illusion, although with such low intelligence, the DM may rule it probably won't use an action to disbelieve it unless the wizard tells it to (exceptions maybe for pseudodragons, quasits, and the like).

Likewise, both caster and familiar would have to make saving throws if in range observing a medusa.