Rhinovirus

The virus that appears in episode 11 is responsible for causing the common cold. It infects General Cells and turns them into zombies who can only say "Kishaa." This virus disguises itself as a hat and performs various pranks to attract the attention of General Cells, aiming to turn them into zombies. In reality, Rhinovirus has a pentagram-shaped pattern, which is depicted in the series as a hat decorated with a yellow star.