Q: Passage: "Butterfly Effect" is a song by American rapper Travis Scott. It was released to digital retailers on May 15, 2017, through Epic Records. The song was written by the rapper and Shane Lindstrom, with production handled by Felix Leone and Murda Beatz.

Question: Based on this passage, when did butterfly effect come out travis scott? Let's give stream of consciousness first:
The important part for answering this question is: It was released to digital retailers on May 15, 2017, through Epic Records. Therefore, the final answer is May 15 , 2017.