Loop is a short animated film from Pixar's SparkShorts programme, first released in 2020, telling a gentle story about two children learning to communicate during a canoe trip. The woof woof sound is a brief, cartoon-style bark taken from that film and trimmed into a repeating loop for soundboards. Because it is short, clean and immediately easy to recognise, creators keep reaching for it as a lighthearted animal reaction, especially in pet videos and comedy edits where a single bark would feel too abrupt.