The Sonic Resonator is a new acoustic tool — an industrial sound amplifier used for mining and creature interaction. The advanced variant is the Feedback Resonator.
It is story-critical. It is the only tool that clears the glowing bloom infection sealing the Infested Caves, destroys the three bloom cankers required for the Axum Vision Adaptation in the Alien Ruins questline, and expels a lodged Tongue Thief parasite (the Survival Multitool cannot). Effectively, major progression gates are keyed to this one tool.