¿Who is stronger, Onslaught or Sandman?

Onslaught is a comic book character created by Marvel Comics and is known to be one of the publisher's most powerful and feared villains. He is a cosmic being created by merging the minds of Charles Xavier and Magneto, two of Earth's most powerful mutants. Onslaught has a number of supernatural powers, including the ability to manipulate people's minds and behaviour, superhuman strength and the ability to manipulate magnetism. He is also virtually indestructible, making him a formidable foe for any hero who confronts him.

Sandman, also known as William Baker, is a fictional character in the Marvel Comics Universe. Created by writer Stan Lee and artist Steve Ditko, Sandman first appeared in Amazing Spider-Man #4 in 1963. Sandman's powers stem from his ability to transform his body into sand, granting him incredible strength and the ability to reshape his form into various shapes and sizes. His sand form allows him to absorb and repel force, making him nearly invulnerable to physical attacks. He can also use his sand form to travel long distances by riding the wind. Sandman's backstory is complex and often tragic. He grew up in an abusive household, and turned to a life of crime as a means of survival. He was eventually incarcerated in prison, where he underwent an experiment that gave him his sand-based powers. Initially, Sandman was a villain and frequently clashed with Spider-Man. However, he has also had periods of heroism and redemption, most notably when he became a member of the superhero team known as the Thunderbolts. One of Sandman's most notable strengths is his ability to control sand and manipulate the environment around him. He can use his sand form to create weapons, shields, and even control the movement of sand around him to his advantage. His abilities also make him a formidable opponent in battle, as he is able to absorb and redirect attacks. Overall, Sandman's powers and strength make him one of the most unique and interesting characters in the Marvel Universe. His tragic backstory and complex relationships with other characters add depth and nuance to his character, making him a fan favorite.