The Eidolon Hydrolyst is a towering, spectral entity with a biomechanical design, featuring elongated limbs and a hunched posture that exudes menace. Its body is composed of a translucent, energy-infused carapace that glows with an eerie blue-green luminescence, highlighting intricate internal circuitry and skeletal structures. The surface is smooth yet etched with glowing runes and patterns, suggesting ancient Orokin technology, while its head is crowned with multiple, horn-like protrusions that emit pulses of light, signaling its connection to the Void.