Explore a groundbreaking physics colloquium that presents the first experimental observation of Pines' demon in the multiband metal Sr2RuO4. Delve into the world of plasmons and learn about a unique type of acoustic excitation predicted by David Pines in 1965. Discover how electrons in different bands can create a "massless" excitation that may play a crucial role in the low-energy physics of multiband metals. Examine the experimental evidence for this elusive phenomenon, including its gapless nature, critical momentum, and room temperature velocity. Gain insights into the significance of this discovery, which confirms a 67-year-old prediction and suggests that demons may be a common feature in multiband metals. Analyze the implications of this finding for our understanding of complex electronic systems and potential applications in materials science.