You want to prank your coworker, use this Google Spreadsheet prank script and it will turn a sheet into a message using cells.
The prank (the script) will make a copy of the sheet that is edited and, letter by letter, display a message by changing the color of the cells.
The intended use of this prank is for a spreadsheet that you and your prank target collaborate on.
Check the youtube video:
You can find the how-to and the script here: https://howtogapps.com/google-spreadsheet-prank/
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