Nebsock emerged when the antagonist Daruizen fused a Mega Part with an ordinary bird, creating a humanoid bird monster. Its name originates from the Japanese term "nebusoku," signifying lack of sleep. Displaying distinct avian traits, Nebsock embodies the Byogens' pathogenic influence. This antagonistic entity actively targets the protagonists within the narrative. Nebsock met its end when Cure Earth purified it using her abilities. Following this defeat, the Byogens judged Nebsock a failed experiment and decried its creation as wasteful.