Their name conjures visions of some kind of a psilocybic hell—say, that clammy, grope-y (and worst of all, campy) pit of hands from Labyrinth—or worse, just some mush-headed Rainbow Gathering jam band (I guess I already said “psilocybic hell”), but the reality of Fungal Abyss is both darker and far more appealing than all that. The band is the improvisational psychedelic side-project of local metal leviathans Lesbian, and for the month of August they’ve taken up a weekly residency at the Comet, where they keep things heavy and heady, lifting off from low, gut-rumbling bass grooves to high arcing stratospheric guitar riffs, without ever drifting entirely into space. Opening tonight’s installment is the deeply knowledgeable DJ Veins, a veritable Yoda of all things kraut, psych, experimental, and beyond. Hold on to your dome. With Ayahuasca Travelers. ERIC GRANDY

Wed., Aug. 24, 9 p.m., 2011