For this trick,you will require:
Clown or Death monster(Preferably Death,of course)
Battnel level 20
2 Big Pita Fruits
1 Wind crystal
Step 1.Take the two monsters to the 1st floor of the tower.
Step 2.Now take them both out,and line the two up so that Death is able to fire a spell at Battnel.Set their AI to 1 so that they dont walk in any other direction.
Step 3.Have Death fire LoDown at your Battnel until it reaches level 1(if Death runs out of mp,then you must feed it the Big Pita Fruit.)
Step 4.Once the Battnel reaches level 1,set the AI back to normal again,and use the Wind Crystal to escape.
Step 5.Go to the Monster Hut and take a look at your Battnels status.
Step 6.Rejoice,dance,do whatever happy you want since hp,defense and attack reached 250!
Dont worry about the mp,if you feed Battnel a herb,it will regain 50 mp.