Hypolydron, Captive Mind

Hypolydron, Captive Mind, is a Vex Mind (called a Vex Hydra in dialogue) held captive by the House of Dusk inside a Fallen shield in the Well of Flame on Nessus. It was introduced in Episode: Echoes, in the Battleground: Delve activity.

The Kalliks fight in the final cavern ends with Kalliks's defeat, which releases Hypolydron. Afterward it teleports around the room, avoids attacks and summons Vex reinforcements, including Compelled Aggressors. Destroying Hypolydron completes the activity.