How do i make an object greyscale but only shows color when overlaps an object?

How do i make my objects in my game greyscale but only shows color wherever an object of my choice is overlaps with the greyscaled object?

If the entire sprite needs to be colored, then you can simply add a condition - Sprite is overlapping Mask : Sprite set effect "Grayscale" disabled.

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If you want to show only the overlapping part of the sprite in color, I'm not sure how to do it. Maybe this will help:

https://www.dropbox.com/s/bskzrw0b8xea80n/ColorMask.c3p?dl=0

thanks exactly what im trying to do, thanks alot again bro :)