The Dink Network

Have you asigned the script to a sprite?

Oh and also it can't be invisible, then it doesn't work.
Instead make it a normal sprite in the editor and put this in the main procedure instead, as msdink suggested (But I forgot, sorry).

void main(void)
{
sp_touch_damage(&current_sprite, -1);

sp_nodraw(&current_sprite, 1);
}

And if you want him to pass later just give him a touch damgage of 0 when a global has a certain value.