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.
Ooh - Jeff Bezos, and some way to irreversibly triple every non-executive Amazon worker/contractor’s pay, plus full healthcare. He can afford it and Amazon has enough direct and indirect workers that it’ll be felt throughout the country and the economy, and other companies will eventually be forced to compete, raising living standards for most people (and increasing tax revenue).
End with a tweet supporting an inflation-linked living wage, Medicare for All, and UBI.