This is basically a dark, looming ostinato repeated a few times with variations. This is very fitting for an "Oh crap" kind of moment, and it might make for a decent boss theme. Maybe. Please enjoy and review if you'd like to.
VST Plugins I own: EW Symphonic Orchestra Gold, EW Hollywood Brass Gold, Cinematic Studio Strings and Studio Piano, Soundiron A.P.E. Micro and Olympus Elements, Sonokinetic Ostinato, Native Instruments Monark, a few free effects and synth plugins