"Bad Blood" is a popular song by American singer-songwriter Taylor Swift, featuring a remix version with guest vocals from rapper Kendrick Lamar. It was released as the fourth single from Taylor Swift's fifth studio album, "1989," in 2015.

"Bad Blood" is a pop and electropop track with a catchy and edgy sound. The song's lyrics address a falling out between friends or acquaintances, with Taylor Swift expressing feelings of betrayal and hurt caused by someone she trusted. The metaphor of "bad blood" represents the negative emotions and conflicts that arise in the aftermath of a fractured relationship.

The song was written by Taylor Swift, along with Swedish producers Max Martin and Shellback. The remix version featuring Kendrick Lamar adds his rap verse, providing a contrasting perspective to the situation described in the song.

Upon its release, "Bad Blood" achieved massive commercial success worldwide. It topped the charts in multiple countries and became one of Taylor Swift's most successful songs. The song's catchy chorus, Taylor Swift's powerful vocals, and Kendrick Lamar's impactful contribution resonated with audiences, making it a crossover hit in both the pop and mainstream music scenes.

The music video for "Bad Blood" features Taylor Swift and a star-studded cast of her friends portraying fierce and stylish characters in an action-packed storyline. The video's visuals, inspired by action movies and comics, became a highlight of the song's promotion and garnered attention for its impressive production.

"Bad Blood" received positive reviews from music critics, who praised its catchy sound and the addition of Kendrick Lamar's verse in the remix version.

Over time, "Bad Blood" has remained a fan favorite and one of Taylor Swift's most recognizable songs. Its powerful sound, relatable theme of dealing with conflicts in relationships, and the intriguing collaboration with Kendrick Lamar have made it a significant and beloved track in Taylor Swift's discography, capturing the essence of emotions involved in challenging interpersonal dynamics.