To beat the Lions head in Agrabah you need to never be in front of it for starters because it will constantly shoot a giant ball of flame out of its mouth. Also don't pay attention to the Heartless that it lets out because killing them doesn't do anything it will just let out more. To beat the lion's head you must climb onto the back of its head and hack away at its eyes with your keyblade (each eye has its own health bar). When you are on its back the Lion's head will shoot homing lasers at you from its eyes and you must dodge roll to escape them. Also if you do too much damage to its eyes the lion head will shake you off and you must climb back on its head and do the same process over again (while dodging heartless, fire, and homing lasers of course).