If they touch him, he is encased in ice for a few moments and invulnerable to attacks until he breaks free. To defeat a Li'l Brr, just spin next to them to reduce them to stones. Then kick or stomp the stone. However, if Mario kicks the stone into the water, the Li'l Brr is reformed. Also, when the Li'l Brr is reduced to stone, it can bounce around until it hits a source of water, so Mario/Luigi has to move fast to defeat it.