Icarus Sandals are the fourth treasure you get. You obtain them after you beat Circe, Chapter 4, Book 1. They sometimes (50% chance), resist stunning attacks from enemies. Their upgrade, Boots of Theseus, have 100% chance of resisting it, making Lex invincible to stunning attacks, if used. The Boots of Theseus are obtain when the Minotaur is defeated, Chapter 6, Book 1.