I've thought it would be cool to make a virus that doesn't do the usual but a specific person.

You the programmer get a request to target John K Smith you make a virus specifically for that person. Then the virus is released where infects anything it can and if it finds John K Smith it deletes or permanently encrypts the info.

Metal Gear Solid 2: Sons of Liberty. It is a fun problem to think about - you don't want to reveal the target, but you also don't want to be detected (gotta poison backups)... so indiscriminate destruction doesn't work.

"Terminator"

There are certainly companies & methods, but "getting rid of social presence" is more of solution than an end, so it depends on what you are actually trying to accomplish.

Say my nudes which I shared with my ex got leaked and are all over the tumblr and porn sites.

The blog I created 10 ago bashing homosexuals is now a problem.

I used racists slurs against someone on an forum 5 years ago which now show up as top results.

etc. etc. you get the point.

I will of course share all the necessary credentials with the target company.

you actually have the wrong idea then. You would want to in fact, increase your media presence 10-20x. Paying people to maintain false accounts with various real & fake pictures of yourself claiming residence in places you have lived or traveled. These large active social media accounts will provide a haystack buffer for your real account which you will gradually provatize and hide.

Generally what you are asking for is not currently possible. You can make requests of search engines to not show links, you can send DMCA takedown requests to places that have photos, and you can plead with forum mods to delete your posts. You can ask the Internet Archive to delete pages about you.

But none of that protects you when some kid who made a copy of things and posts them again and again on some random forum site like one of the chan sites or some other home grown forum. Eventually it will be indexed again and you'll be back trying to whack it out of existence. Sorry.

Yep, as mentioned above, often "chaffing" is a more realistic approach. Sowing confusion is easier than refuting or censoring.

Often you can't take back what you said, BUT you can change e.g a non archived profile image to associate comments with a fake account.

Related question: is it best to give a child a unique, or very generic name?

Currently I lean towards generic, as unique names or pseudonyms can be created on demand.

All of this intersects in interesting ways with "real name" policies IMHO

This was sort of the plot of the Orson Welles film "Mr. Arkadin" (aka "Confidential Report").