Invisibility cloak

When you had Arachne, the seamstress who had outdone the Goddess of Weaving, that was only natural. Her Noble Phantasm, Argaleiós Arákhnēs, was what had allowed me to make not only that strip of cloth to hide Lisa’s identifying freckles, but also the cloak of invisibility that the three of us were huddled under.

And all it had taken was an old, unused bed sheet.

After that, Medea had taken care of the rest.