Sprite shrink nearer it gets to an object

How do I make a sprite shrink gradually the nearer and nearer it gets to another sprite until eventually touching the other sprite and disappears?

Use distance(x1,y1,x2,y2) expression to control opacity.

Edit: I meant to say use distance to control size! But probably after reading last word about disappearing I've put opacity instead of a size. Sorry about that.

is there any way I can shrink it the closer it gets to an object and use the opacity?

You could use the same distance expression to change the size if that's what you are after.

shinkan lol, it's alright. For the distance(x1,y1,x2,y2) What event do I use though? Set Scale? Do I select my sprite?