Arachnus is a fictional alien species that appeared in Metroid Fusion. Arachnus represent deep-sea turtles that inhabited the Earth billions of years ago. In Metroid Fusion, Samus confronts an Arachnus in the early part of the game, then defeats in to recover the Morph Ball ability. Aracnus will roll into balls to attack. They can be avoided by clinging to ledges nearby or by jumping over them.