“Pika pika” is widely recognized online as part of Pikachu’s signature speech from the Pokémon franchise, especially through the anime. Short voice snippets like this spread easily in meme edits, fan videos, and reaction posts because they are instantly identifiable even at only a couple of seconds long. The sound stays popular thanks to Pokémon’s long-running global reach and Pikachu’s role as one of the most recognizable anime mascots. Creators keep using it whenever they want a quick cute reaction with a familiar character voice.