For decades, science fiction has imagined electronic devices that spring to life on demand, function as programmed, and then vanish without a trace. Today, transient and bioresorbable electronics are making that vision a reality, sparking revolutionary progress in biomedicine, environmental stewardship, and hardware security. Yet one critical barrier remains: a fully transient power source with the same disappearing act. Microbial-based biobatteries have emerged as strong contenders, harnessing the power of microorganisms-found virtually everywhere-as natural biocatalysts. However, toxicity and health risks have limited these systems to single-use, often incinerable applications. Here, a transformative approach: a transient biobattery powered by commercially available probiotics that dissolves harmlessly is introduced, releasing only beneficial microbes. Fabricated on water-soluble or pH-responsive substrates, this biobattery capitalizes on a 15-strain probiotic blend to generate electricity across diverse electrode materials. By manipulating device length or encapsulating it with pH-sensitive polymers, power delivery can be fine-tuned from 4 min up to over 100 min. A single module outputs 4 µW of power, 47 µA of current, and an open-circuit voltage of 0.65 V. This groundbreaking design ushers in a new era of safe, effective transient bioenergy systems, opening unprecedented opportunities in biomedical implants, environmental sensors, and disposable electronics.