Step 1: Step 1: Desktop Screenshot
Step 2: Step 2: Slide 2
Make sure your message has a button or 2 for the victom to press. Right click on the shape the button will be, insert text, and make the button say what you want it to say. Then, click some blank space in the page, and reselect the button by clicking it's border. Then, go to action, insert hyperlink, and make it hyperlink to next slide. Do that for any buttons you have on the powerpoint. The next step is un auto advancing. Go to animations at the top toolbar, and deselect advance slide on mouse click. Finally, insert a second slide, and edit how you want. I suggest it says just kidding, so the person knows its a joke.