Most people in Miguel Street have always regarded Man-man as more than a little eccentric, if not actually mad. Even by the standards of the neighborhood, he's a colorful character, a man who engages in all kinds of strange behavior, whether it's putting himself forward for public office, despite having no chance whatsoever of winning, or getting his dog to defecate in a cafe whose owner had earlier told him to get out.
But when Man-man loses his dog after it's run down and killed by a car, eccentricity descends into outright madness. In the wake of the tragic accident, Man-man seems utterly bereft. He wanders the streets for days, looking dazed and lost, talking to himself and seemingly oblivious to those around him.
At the very least, it appears that Man-man is being torn by an inner conflict relating to how he should deal with his grief. The loss of a loved one—or, in this case, a beloved pet—can often have this effect on people. The problem with Man-man, however, is that he's already a tad eccentric to begin with. This inevitably makes it more difficult for him to come to terms with his loss.
And so, there's a tragic inevitability about Man-man's subsequent descent into outright madness. Unable to deal with his inner torment, he retreats into a fantasy world in which he is the new messiah. Man-man is so certain of this that he has himself crucified.
This lurid spectacle rapidly descends into farce as members of the crowd start throwing stones at him. Though this is what Man-man intended to happen, he demands to be released from the cross so that he can settle accounts with those who are pelting him with stones.
Before long, the police have taken Man-man away. The authorities then keep him for observation for good, a further indication that Man-man has taken leave of his senses.