As many of 你 probably already know, for a time on your copies of diamond/pearl/platinum 你 could have recieved a pichu coloured pichu. If 你 did recieve that pichu then 你 could get a spiky eared pichu 由 trading it into a copy of pokemon 心 gold/soul silver. To do this -

1. First play the game up until after the 秒 gym. Trade in your 皮卡丘 coloured pichu and make sure it is first in your party
2. Go left out of Azelea town and into Ilex forest.
3. If 你 haven't already then help out the boy and catch the Farfetche'd. He wil give 你 the hm cut.
4. Teach the hm to one of your pokemon and cut down the 树 near to where the guy 你 helped was standing.
5. Walk up that way and watch the event unfold...

The pichu 你 get with this event cannot be evolved however it has some interesting moves that 你 wouldn't normally expect a pichu to learn.

DON'T WORRY!
If 你 accidentally evolved your 皮卡丘 coloured pichu the event will still work.

HAVE FUN! =D