Scratch

I think what you are trying to do can be done best using one of the Broadcast blocks.  When you want one sprite to send a message to another sprite to do something, the Broadcast blocks will do the trick.  Look for them in the Control tab.

In the script that is going to send the message, snap in either the Broadcast block (if you want to send the message and then immediately move on to the next block) or the Broadcast and Wait block (if you want to wait until any scripts that receive the message are finished before moving down to the next block). Then, click on the dropdown menu (little triangle) and choose New.  Make up a message name that makes sense to you, like "Game Over" or whatever you like.

[blocks]
<broadcast[ Game Over
[/blocks]

On the sprite where you want to recieve the message, use the "When I Receive" block to start a new script that will do what you want it to do when it gets the signal.

[blocks]
<when I receive[ Game Over
<show>
[/blocks]