Sheegoth looks similar to a turtle with a spiky frozen back. To defeat Sheegoth, you have to stay away from it. Then when Sheegoth charges up a power ball in its mouth, dodge it, and shoot power balls (or missiles) at it. Keep repeating this until Sheegoth dies. (Note) Only shoot Sheegoth after it attacks you. If you defeat Sheegoth, you will get the wave beam.