Pillow is a character from the web series Battle for Dream Island, and this clip is tagged by fans with its later seasons, Battle for BFDI and The Power of Two. In that community, short character sounds are often clipped, shared and reused in fan edits, memes and reaction videos rather than kept only inside episodes. A pillow-muffled scream fits that style perfectly, because it is instantly recognisable as a cartoon outburst while still sounding soft enough for comedy. That mix of fandom recognition and easy reuse has kept it circulating online.