Fireflies was released in 2009 by Owl City, the solo project of Adam Young, as the lead single from the album Ocean Eyes, and became a number one hit in the United States. Its light electronic production and insomnia daydream lyrics made it an early internet era pop staple. Slowed and reverb edits later circulated on YouTube, SoundCloud and TikTok, where creators reframed the upbeat song as a sad nostalgic track. That version stuck for edits about growing up, distance and lost summers, keeping the melody familiar while changing its emotional meaning entirely.