During the early weeks of the pandemic, Tim Hayward spent 14 days in a coma. He remembers this time vividly – his days and nights filled with strange, incandescent visions and hallucinations. That experience is something he would never choose to revisit but, around the world, large numbers of people are deliberately seeking out powerfully altered states.

In this ten-part series, Tim sets out to better understand a group of substances that induce altered states: psychedelics.

There’s been a surge of interest in their therapeutic potential for various mental health conditions - as well as a range of other clinical possibilities. As research around the world ramps up after years of taboo and prohibition he tries to get to grips with - or at least get a clearer sense of - how science, culture, politics and business might all interact in this changing psychedelic landscape, and what it all might mean.

He also explores what might be happening in the brain during a trip and whether, by studying psychedelics, we might uncover more about consciousness, imagination and even the mysteries of reality itself.

In this third episode Tim hears tales of pixies, hyper-intelligent alien entities and explores a highly unusual molecule found in the glands of a toad.

Contributors:Lisa Luan, neuroscientist and psychologist, Imperial College LondonDavid Luke, psychologist and psychedelic researcher, University of GreenwichChris Timmermann, neuroscientist and psychologist, University College London

Presenter: Tim HaywardSeries Producer: Richard WardExecutive Producer: Rosamund JonesEditor: Kirsten LassWritten by Tim Hayward and Richard WardSound Design and Mixing: Richard WardResearcher: Grace RevillVoiceover Artist: Sandra-Mae LuxCommissioning Editor: Daniel ClarkeA Loftus Media production for BBC Radio 4