An imaginative Halo fan recently shared some nightmarish concepts of The Flood infecting the equally dreaded Gravemind and transforming it into an even more terrifying biomechanical monster. Master Chief has faced off against some fierce enemies throughout the Halo series, but few are as frightening as the Flood, a parasitic organism that has been sending chills down the spine of even the most battle-hardened Spartan ever since the original Halo: Combat Evolved.