¿Who is stronger, Groot or Buu?

Groot is a character in the Marvel Cinematic Universe (MFCU) who is also part of the Guardians of the Galaxy. Groot is an extraterrestrial being who belongs to the Flora colossus species, a race of arboreal humanoids capable of regenerating and controlling their own plant bodies. In the UCM films, Groot is portrayed as loyal and brave, yet innocent and sometimes childlike in nature. Groot has a very distinctive personality and his vocabulary is limited to the phrase "I am Groot", although other characters seem to be able to understand his meaning based on context and intonation. Groot possesses superhuman strength and stamina thanks to his wooden body, as well as the ability to regenerate and grow his limbs at will. He can also throw sharp spines and control the vegetation around him. Throughout the UCM films, Groot plays an important role in the fight against the forces of evil, even sacrificing himself to save his friends on one occasion. After his sacrifice, a new Groot is born from a branch, meaning the character is essentially immortal.

Majin Buu is a pivotal antagonist in the "Dragon Ball" series, introduced during the "Majin Buu Saga" of "Dragon Ball Z." Created by the dark wizard Bibidi, Buu is an ancient entity with immense power and a malleable, pink physique. Throughout the series, Buu undergoes several transformations, each altering his personality and power levels, including Innocent Buu, Evil Buu, Super Buu, and Kid Buu. His abilities are vast and versatile, encompassing regeneration, absorption, and transmutation, such as turning adversaries into sweets. Despite his initial role as a villain, aspects of Buu's character, particularly in his Innocent form, display a capacity for change and even benevolence. This complexity adds depth to his character, making him one of the most memorable antagonists in the "Dragon Ball" universe.