Magik turns into her Darkchylde form after O.N.E activated the mutant cure on her. She then defends herself from Juggernaut and easily takes out the gem of Cyttorak from his heart, or chest, and destroys it. Not sure if she killed Juggernaut in that portal, or if she just sent him to Limbo.
From – Uncanny X-men Vol. 5 #21