Splash does nothing.
it's ZAP PLATE and you find it underground
go to the bottom of the waterfall at the Pokemon league.
Plates in Diamond and pearl are used to give to Arceus after you caught it. For example, if you give Arceus a splash plate, it will be a water type. If you give it a spooky plate, it will be a ghost type. Also, if you have a plate that is the same type as a Pokemon, it will boost its attacks. For example, if you have a Fist plate and a Pokemon that knows some fighting type moves, if you give the fist plate to the Pokemon that knows some fighting type moves, it wil boost its fighting type moves. -Written by Spencer Camacho
Finding the Insect Plate in Pokemon Diamond requires the use of the HM Cut. It is in Eterna Forest hidden in the wall to the right of the Old Chateau.
there isn't a aqua plate it is a splash plate, you find it underground
Splash does nothing.
In the Underground
the splah plate is to up water pokemon's moves and make them stronger
Insect Plate Dread Plate Draco Plate Zap Plate Fist Plate Flame Plame Sky Plate Spooky Plate Meadow Plate Earth Plate Icicle Plate Toxic Plate Mind Plate Stone Plate Iron Plate Splash Plate
i have heard that splash only works if you are holding a water plate
go underground at route 220 and dig it out
If you have Arceus, then all you have to do is give it one of the plates that can be collected around Sinnoh, for example, the Splash Plate. Then the Arceus will change its type.
You give it to Arceus to change its stats and type.
it's ZAP PLATE and you find it underground
underground
darkrai arceas (with plate)