No, I did not. I defeated her in the new encounter area. Something with some huys travelling on a boat. I think the special power there was about movement.
I didnt roll any dice like what happens in the general store either. I just killed her (for the second time so the definitive one) and just before pathfinder appeared to take me to her speech a card materialized and went into my hand, without time to check what it was. In the aftermath, after levelinv up my guys Seoni had a new item, and was this wand.
The name is the same of the spell. Scorching ray and scorching wand I think, so IMO they are definitely related. I checked in the vault and is a deck 3 item.
Might be worth a shot trying to replicate it if someone had the time to do so.
PS: i seem to have lost the medusa mask (without ever using i, its just not there). Any way of getting another copy in my current playtrough?