In the blogosphere, electronic subgenres mutate at a dizzying pace. Consider seapunk — which you can file between witch house and vaporwave, and which came about an internet decade (say, eighteen months) before PC Music — a style known as much for aquamarine hair dye and early-internet graphics as for glitchy, pop-inclined electronic statements. Ultrademon is a self-described seapunk practitioner, though infrequent Tumblr users will recognize his music simply as solid and somewhat oblique techno. On Sunday at the Golden Bull (412 14th St., Oakland), Ultrademon headlines the Final Fantasy party. Openers include Witowmaker, the frantic techno outlet of Religious Girls’ frontman Chris Danko, and Space Ghost, a local electronic artist and beat-maker noted for his highly refined production. Bobby Peru, a DJ and party fixture from the Trill Team Six outfit, starts things off. Attend for empirical evidence of seapunk’s existence offline.