Dragon Ball Z, Season 1

Nappa:
I...I...I can't move my legs.

Krillin:
Wow Goku, I think you really hurt that guy. He's not getting up.

Goku:
(to Vegeta) He won't be fighting anymore. I suggest you take him back to wherever you came from and get him some help.

Vegeta:
(to himself) He's so confident. How could he achieve that drastic increase in power and speed?

Krillin:
Hey Goku, how did you do that? That was one of the most amazing attacks I've ever seen. What was it?

Goku:
Oh...it's the Kaioken attack. It's like a massive upsurge of energy. Everything is heightened, power, speed, even hearing and vision improve dramatically. You sort of become a super-self. But it can only be sustained for a short time, so you have to get the job done quickly.

Krillin:
That's so great! Do you think you'll be able to teach me how to do a move like that someday, maybe, huh?

Goku:
Maybe.

Vegeta:
As usual, I have to do everything myself.

Krillin:
Why didn't you use that Kaioken to attack him in the first place Goku? Heh, with a move like that, you could've taken him out anytime you wanted to.

Goku:
That's true. I could have, but the problem is there's always a chance that the increase in energy could've destroyed my body. But I'm still here, aren't I? Yeah.