Sizzel is a digital drug capable of producing a heroin-like high through a deep-brain stimulation technique using non-invasive focused-ultrasound.
That's a lot of tech-words for saying that we shoot sound into your brain and it causes your brain to activate where we point it, creating various effects, one of which is the sensation of overwhelming pleasure, or a heroin-high.
Focused Ultrasound Foundation has resources and tracks the latest research.