An adorable little tree
Groot is one of the most popular Marvel characters of recent years, revealed to the general public by the Guardians of the Galaxy movies. Indeed, in the first movie was an adult humanoid tree creature who worked as a bounty hunter throughout the galaxy with his partner Rocket, a genetically modified raccoon. But everything changed when they crossed paths with Gamora, Star Lord and Drax and, somewhat unwillingly, saved the galaxy together. At the end of the movie, Groot sacrifices himself to save his new friends but Rocket recovers some twigs and manages to grow a new Groot. So he is an adorable baby at the end of the movie and then a child/teenager with all that entails in the next movie as well as in the Avengers Infinity War and Endgame movies.