
Arachnus is another enemy Samus will face on SR388, one of three main foes outside of the Metroids, and you'll only face it once. Arachnus likes to shoot out wave attacks, ones that are easy to dodge by jumping. It also likes to curl up in a ball before charging at you. Again, something that can easily be avoided by jumping. At some point, Arachnus will eventually curl up again, but this time jump in your direction. As soon as it lands, simply jump over to avoid getting hit.
Arachnus isn't that difficult of a foe to defeat, but you'll only be able to cause damage to it when it's out of its shell and its red body is exposed. But once it is, Missiles do the best job at defeating it. Once you have defeated this Boss, you will earn the Spring Ball.