Hitting a box

[The achievement]

Hi guys, i have a question mark box in my game like mario games, and you get an easter egg right when you hit it, ya the egg comes out when you hit it, but if you keep hitting it, the eggs can coming out each time you hit teh box. is there a way to only do it one time?????????

[Novice]

Make an actor varuiable wich will be 0 when created and when hit the first time use
if([variable]==0)
{
Create Actor (EGG);
[variable]=1;
}