Elon Musk has promised to give away $1m a day until the US election to someone who signs his online petition.
The Tesla boss is backing America PAC, a political group he set up to support Donald Trump's bid for the White House.
He posted on X: "Every day, from now through Nov 5, @America PAC will be giving away $1M to someone in swing states who signed our petition to support free speech & the right to bear arms!
"We want to make sure that everyone in swing states hears about this and I suspect this will ensure they do."
The first $1m (£767,000) has already apparently been awarded to a man named John Dreher during a campaign event in Pennsylvania on Saturday.
X This content is provided by X, which may be using cookies and other technologies. To show you this content, we need your permission to use cookies. You can use the buttons below to amend your preferences to enable X cookies or to allow those cookies just once. You can change your settings at any time via the Privacy Options. Unfortunately we have been unable to verify if you have consented to X cookies. To view this content you can use the button below to allow X cookies for this session only.
Mr Dreher pumped his arms in delight as he emerged from the audience to collect the prize, telling Musk he was "ecstatic" to receive the oversized cheque.
"By the way, John had no idea. So anyway, you're welcome," the billionaire said.
Musk's event in Harrisburg was his third in Pennsylvania in as many days.
He told the audience that if Kamala Harris wins in just over two weeks' time it will be "the last election", suggesting the US will cease to exist.
Musk also said the attempts on Donald Trump's life show he is a danger to the establishment in a way his rival is not - and claimed that's why no one has tried to kill her.
"Assassinating a puppet is worthless," he told the audience, repeating a line he's previously put out on social media.
Attendees at the Pennsylvania rally also had to sign the petition, which allows America PAC to get their contact details with an eye to getting them to vote on 5 November.
The petition reads: "The First and Second Amendments guarantee freedom of speech and the right to bear arms. By signing below, I am pledging my support for the First and Second Amendments."
Opinion polls put the US election on a knife edge and the outcome is likely to be decided by who wins in a few states where it could go either way.
Read more:
Trump paces the stage in silence after mic cuts out
Harris risked a lot for Fox interview - it may not have paid off
Musk is the world's richest person and is worth $274bn (£210bn), according to Forbes, so the approximate $17m (£13m) he's vowed to give away is a minuscule fraction of his wealth.
Spreaker This content is provided by Spreaker, which may be using cookies and other technologies. To show you this content, we need your permission to use cookies. You can use the buttons below to amend your preferences to enable Spreaker cookies or to allow those cookies just once. You can change your settings at any time via the Privacy Options. Unfortunately we have been unable to verify if you have consented to Spreaker cookies. To view this content you can use the button below to allow Spreaker cookies for this session only.
👉 Tap here to follow the Sky News Daily wherever you get your podcasts 👈
He has so far supplied at least $75m to America PAC, according to federal disclosures, making the group an important part of Mr Trump's re-election campaign.
However, the group has had problems hiring campaigners in recent months, having fired two major contractors since July who were tasked with knocking on front doors.
America PAC is one of several major political action committees in the US.
Such groups can raise and spend unlimited amounts of money in support of political candidates, on the condition that they do not coordinate with their campaigns or give money to them.
Mr Trump has said he will give Musk a government job if he becomes president again.