Most likely not. Events don't usually reopen once they've been done.
by an event
You have to have the shiny pichu from the gamestop event.
Yes it can, but where is Shiny Pichu anyway?
...nope...
not sure
no
nope, you still need the event one, although you catch one million shiny pichu :D
To get the Spiky-Eared Pichu you have to bring the special shiny Pichu from a Gamestop event to the Ilex Forest Shrine.
No, you do not need the National Dex for the Shiny Pichu event being held at Gamestop stores, all you need is the Sinnoh Dex for the Gamestop event.
A rare Pokemon you can get by going to an event at places such as Gamestop and Toys R Us. Some examples are Arceus, Darkrai, Shaymin, and Shiny Pichu.
The 'Pikachu Coloured Pichu' (actually a shiny Pichu) can be found as part of a Nintendo Event.
arceus or shiny pichu event