This cheat can only be done in the third disc. First, go to the Northern cave and look for mole like creatures with a star above thier heads, also holding a knife and a lantern. Steal an elixir from them and then run away. After that, look for these small creatures in a floating pot. They will say "Gimme' an elixer". Give them one. Then kill it. Each one killed will give you 1,000 AP. You can not kill them unless you give them an elixer.