I had something like this happen early with one of my early brews, though not as dramatic... due to a too-large container of malt extract and some bad math on my part, an extract batch that was supposed to be a spiced amber ale for the holidays turned into a spiced black-as-night who-knows-what, OG 1.075ish instead of 1.045ish. Still not sure what happened there, but the result was delicious! Almost resembled a belgian strong dark to our tastebuds. Sad thing is it was a one-gallon batch.
Fermenting: Uwharrie Mountain Mead, Novemberfest
Conditioning: Bohemian Pilsner
Drinking: Edwort's Apfelwein, Motueka Wheat, VIP ESB, RBC Hidden Pipe Clone, Naked Red