Friendly Wither, or Pink Wither - Attracted to sugar, restores health to all surrounding mobs, and applies bone meal to all eligible neighboring blocks. It also has the ability to grow roses, dandelions, tall grass, and ferns on grass blocks, due to the bone meal. Starts off with one head, and feeding the Friendly Wither sugar will grow another head (up to three) and increase the range of these effects. If you want to spawn a Friendly Wither, you will need to place a pink wool, with a flower pot containing a rose on top. As with their evil counterpart, they drop Nether Stars. It is still classified as hostile mob, though its behavior is not hostile. The Friendly Wither is also considered undead, and will be hurt by potions of healing and healed by potions of harming. This is because the Friendly Wither has the same Mob ID as the Wither Boss. The Friendly Wither has no health bar. Summary from minecraft.net