Grandpa

Grandpa is a special monster found at 1313 Mockingbird Lane.

His special attack doesn't harm you, but does scatter all your items around the level randomly, including the ones you have equipped. If you're going to fight him in a way that risks triggering the attack, it's highly recommended to kill all other monsters on the level first, since it leaves you unarmed and unarmored.

Defeating Grandpa

 * Eat the Gregere Berry. This turns you green. While you are green, Grandpa will not use his special attack.
 * If you don't have the berry or its effect has worn off, you may attack Grandpa from outside the range of his special attack.
 * You may kill him very quickly, within one or two hits, before he has a chance to use his special attack (high-powered grenades seem to do the trick).
 * If none of these are an option, you are unfortunately limited to hitting him, getting turned into a mouse, gathering your stuff, hitting him again, and repeating until he falls. Can be done, but is quite tedious.
 * You may avoid Grandpa entirely by using a Jackhammer or some sort of teleportation to enter the doorless room where the map is kept. You may also lead him away and slip into his room, step onto the teleportation trap he guards, and be teleported to the map room that way.