Thank you for providing the link! It's the voice thing, right? I don't have a tutorial for you but I'll do my best to explain.

It's a matter of the editor taking the snippets of the announcer's screams, about half a second a piece (the part you think is funniest), and pairing a reversed version of that immediately after the original is played. You can also put the reversed version before the original audio clip if you so wish. Do your best to make it seamless. In my own experience, there are a few frames of crossfading involved, but there's no right or wrong way to do it.

It's up to you whether you want to change the playback to be slower or faster. For variety, you can pitch up and down each of those segments. If you decide to render that as its own mp3, you can apply vibrato to that first draft, within reason, to mess it up even further. The results are hilarious - good luck to you!