The High Dog meme, also widely known as Stoner Dog, features an Australian Shepherd named Riley with a hilariously squinty, blissful expression that suggests he's under the influence. It first surfaced on Reddit in 2011 after a user shared the photo of their pet looking suspiciously relaxed. The image quickly became a staple of '10 Guy' style humor, used to represent hazy logic, philosophical stoner thoughts, or just general contentment. Its enduring popularity lies in the dog’s relatably goofy face, making it the perfect canvas for any joke involving being 'spaced out' or genuinely happy.