Only one time use.
Think of like world leaders, celebrities, ya know 😉. Are you gonna make them do some embarassing things, or illegal acts.
My answer:
spoiler
Take control of an NSA agent with access to the most powerful hacking tools, hack everyone’s phone, install a program that randomly have a popup at random intervals, the popup message says “I’m watching you”. This also tries to spread itself to any other phone it can connect to. Pure chaos 😈
Pretty sure I can do this in a minute, depending on how good the NSA tools are.
take over Trump on inauguration day just as he’s about to take the oath. claim the election was rigged in my favor by the Russians and everyone I know was in on it also that I’m (he) a Russian spy. call all magas mentally retarded and they should drink bleach to cleanse the world of their filth.
finally take a swan dive down the stairs and break my neck.
The best part of this would not be the act itself but the insane mental gymnastics that Americans would put themselves through to deny or justify it so as to result in, ultimately, no change at all.