You have to go to the venisaur party thing and beat all 3 of the rounds (Or 2) and you will get it. Hope this helps!
You're probaly not speaking clearly or not holding the Z or L button.
Sometimes Pikachu will run away. But don't worry, the first time this happens you'll get the Megaphone to call Pikachu.
On any map, play days discovery days, daring days, move your joystick in any direction and hold. You should see your level selection thing go all over the place. Eventually Pikachu will get dizzy.
Whe you have the megaphone you can use it to knock items of the tree. Aim at the tree and hold the speak button and say something. If the bubble hits the item, if will fall off the tree. Using this I had all the Caterpie on the butterfree level to evolve.
To make Pikachu mad and use thunder bolt say: Playstation, Nintendo64, Dreamcast, or Electric rat.
Tell Pikachu to thunder a tree with caterpie food and you get cater pie food.
I found that if you tap a, b, or a&b huge pokemon will appear. I caught a 200in Seaking that way!!!
If you were looking for Hey You, Pikachu! for N64 cheats, then you might also want cheats for: