Scratch

I think your explanation of the problem is too vague, maybe you could elaborate a bit?

Try using Broadcasting.

<when[ Stage ]clicked>
<next costume>
<if><( background # <=> 2 )>
<broadcast[ Enemy_Appear
<end>

Now, here's the script to put into the enemy.

<when green flag clicked>
<hide>

<when I receive[ Enemy_Appear
<show>

You could also use

{if <level = 2>}
        [show]
{else}
        [hide]
{end}