Ok. So in my copy of Pearl, I started a Turtwig-only runthough. With the implyed HM Slaves.

And so I'm at Palkia, as of now, with Cyrus' evil ass thoroughly whuped. So I was fighting Palkia, and this is what happens.

Go Turtwig!
Used Hyper Potion
Palkia did Water Pulse
Turtwig is Confused
Turtwig Hurt himself
Palkia did Dragon Claw
Turtwig used Hyper Potion
Turtwig hurt himself
Palkia did Spacial Rend
Turtwig used Hyper Potion
Palkia used Dragon Claw
CRITICAL HIT!
Turtwig used Leaf Storm (x3 Damage, since he was at 1/3rd his HP.)
CRITICAL HIT!
Palkia Fainted

Yeah. Epic lolz were had.