He sacrificed himself to save the life of the Guardians against Ronan, but Rocket was able to salvage some of his roots, which grew into a new Groot, who, according to writer and director, James Gunn, is the offspring of the original Groot. By the mid credits of Guardians of the Galaxy Vol. 2 and the entirety of Infinity War, he is a preteen, who doesn't really listen to his teammates/adoptive family. He started to take notice of Thor when the Guardians found him floating unconscious in the wreckage of the Statesman, after Thanos destroyed it, and admired his heroism when he risked his life to create the axe of Stormbreaker. This motivated Groot to dismember his own arm to use as the Stormbreaker's handle, which was then able to restore Thor's life. Although, his powers allowed him to regrow it.
After Thanos acquired all six Infinity Stones he used the combined power to cut the universe's population in half, which included Groot. He called out "Dad" to Rocket, who could only watch in despair as Groot disintegrated.
- Guardians of the Galaxy (2014)
- Guardians of the Galaxy Vol. 2 (2017)
- Avengers: Infinity War (2018)
- Avengers: Endgame (2019)