You get it by doing lots of missions. Then, you get it from a Elekid.
he is in amp pains if you have a secret slab and a mystery part
concealed ruins with secret slab or mystery part
You must have a Secret Slab/Mystery Part. He is in Dark Crater, 10F.
zapdos is in amp plains on 7F but you need a mystery part or a secret slab
The secret slab enables you to meet legendary Pokemon after you reach the marine resort.
Yes, you can find Celebi in mystifying forest if you have the secret slab and go to the 10th floor.
It is in Final Maze 40F you need secret stone plate or enigma part in bag (secret slab or mystery part)
You can find it in Surrounding Sea floor 18 with the Secret Slab or Mystery Part in your treasure.
You can only get the secret slab on Pokemon Mystery Dungeon if you do the following things I tell you to do./Wait for a mission that says,''Help me find the secret slab!''Take it.Then,do the mission and that he/she Pokemon will give you a secret slab. That also helps getting the mystery part. P.S. You can get Celebi on explorers of time, Mew and Jirachi on explorers of sky,Shaymin too. Manaphy and Phione count on every game except for red and blue rescue teams. By the way...How do you get all of the friend areas in red and blue rescue teams?....
the secret,slab and mistry part are 2 itoms that make speshel Pokemon apper in dongens like surrouned sea B18F you find lugia as long as you have on of the 2 itoms in your bag.
It helps you get all of the legendary pokemon.