Mark Twain finds Huck Finn a very interesting character. We know this because he gave Huck his own book in the sequel to Tom’s.
Twain delightfully describes Huck as the “juvenile pariah” and goes on to explain why all of the boys want to play with him.
Huckleberry was cordially hated and dreaded by all the mothers of the town, because he was idle and lawless and vulgar and bad— and because all their children admired him so, and delighted in his forbidden society, and wished they dared to be like him. (Ch 6, enotes etext p. 31)
The mothers of the town think Huck is a bad influence. He is really just an abused, motherless waif whose alcoholic father does not take care of him. Huck is tough on the outside, but suffering on the inside.
Most mothers in Twain’s day felt that his books were a bad influence on their children. You can see why Twain would relate to Huck! They were both misunderstood.