In 2014's Guardians of the Galaxy, Groot made the ultimate sacrifice to save his teammates. In a moment that brought many fans to tears, the sentient tree said, "We are Groot" before burning up in Xandar's atmosphere.
He'd be reborn as Baby Groot (though James Gunn has made it clear that it's a different Groot rather than the same one), a character we've since watched grow up across the course of several movies.
He was a teenager in Avengers: Infinity War, Avengers: Endgame, and Thor: Love and Thunder, but had become an adult by the time The Guardians of the Galaxy Holiday Special and Vol. 3 rolled around.
When the team decided to go their separate ways in the latter, we hear Groot say "I love you guys" in English, with Gunn later confirming that the audience is now able to understand the hero as they're also part of this family. Doing the rounds to promote Fast X, Vin Diesel reflected on that big moment for Groot.
"You know, just...on that front, it was very cool because it meant that the audience is now able to understand the vernacular, the language of this Flora colossus."
"That's a testament to the ten years of loyalty which we've been so blessed with in this franchise with the Groot character and patience to have people wait that long for somebody saying three words," the actor continued. "But, like everything alive, with patience and dedication."
In Vol. 3's mid-credits scene, Groot has undergone another evolution and that's a side of the character we're sure Diesel would be keen to explore down the line.
Guardians of the Galaxy Vol. 3 is currently playing in theaters.