Do a better trick by making your little brother into a little sister ;)

Sounds like he thought magic tricks have Punch Lines!

Punch him in his sleep, douche.

Are you expected to be more mature? If not, ask him if he wants to see a magic trick. Then give him a good smack in the face with your flat hand to leave a niiice big red print on his cheek. Or just be the better person and love him anyways ... that'll make him feel stupid...

The trick was he made your parents not give a shit :P

If he's old enough to dish it, he's old enough to take it. Next time lay his ass out!

Try clubbing him upside the head. Tell him it's a magic trick.

Just realized OP lives in Australia... Don't they have giant spiders and other strange things down there? Depending on how hard core she is I imagine there are plenty of retaliation opportunities...

Wow, that sucks big time OP. I don't think you posted to fish for unwarranted advice, but I just can't help it: would it work to sit your mom/both your parents down and explain to them calmly and clearly, that you are concerned about what happened? Draw a line. That particular thing is in the past, no point in trying to squeeze out a late reaction from them, it wouldn't have an effect. So tell them that in case he's violent again, you would like them to respond appropriately. (Discuss the appropriate response with them so that it's specific. Don't just leave it vague) Also have them tell you whether they support your side in any way, because if they don't then the whole talk can be pointless. Keep calm and speak reasonably and to the point. Refuse to be pushed down!

That's terrible. You may be his sister but he has to be taught that putting his hands on a woman inappropriately in any way is unacceptable.