Mirror is a transformation in Potato Packs, a mod for The Binding of Isaac. It is part of the Potato Pack 1 submod.
+1 Soul Heart.
Pressing the drop input or CTRL button plus an attack direction will cause Isaac to swap places with a reflection familiar.
Granted after collecting 3 of the following:
• My Reflection
• Landscape Mirror
• Portrait Mirror
• Hydrophobic Mirror
• Cursed Mirror
• Item Mirror
Part of the Potato Pack 1 mod.