There are three Paozos in Concrete Man's stage. They all have balls in front of them, then they'll roll or throw them toward Mega Man with their trunks, then suck the ball back, then so on.
The first one is really simple. It has a red ball and collar, so the ball will roll. There is a ladder right above the ground, and Mega Man can easily blast the elephant as long as he hangs on to that ladder. The second one has a green ball and collar, so it will try to flip the ball upwards. Stay near the elephant then start firing. The last elephant also has red gear, however, there is no ladder and there are holes in the ground. So if Mega Man gets hit with the ball when the elephant pulls it back, he will probably fall to his doom right before the checkpoint.
Paozo comes from "Pao," the Japanese onomatopoeia for an elephant trumpeting.