The Great Hydra is a mid boss from Rosenkreuzstilette.
It is a large purple creature with four serpentine heads, and a central body adorned with a purple orb, which serves as its weak point. The heads will shoot spherical shots at the player. The Great Hydra can be skipped by using the Die geplante Zukunft, and the Liebessturm is effective against it as well, as it is capable of destroying all four heads in two uses. In addition, a single fully charged Lustatem aimed at the core will pierce straight through any heads and destroy the enemy.
Two Great Hydras can be found in Heiligtum des Wasserteufels (Trauare's stage), though the second one is only fought if the player takes the higher path.