Magnet (Mario's Time Machine)
From the Super Mario Wiki
The Magnet is an item in the PC release of Mario's Time Machine. It is a horseshoe magnet used by Michael Faraday in his experiments on electromagnetic induction (despite him using an electromagnet and not a permanent magnet like a horseshoe magnet). In 1831, as Michael Faraday is on the cusp of discovering electromagnetic induction, Bowser travels back in time to London and steals the Magnet, preventing him from finalizing his discovery. The Magnet is then exhibited in Bowser's Museum alongside other time-displaced items until Mario steals it back and travels back in time himself to return it to Faraday, albeit without knowing that it belongs to him. Mario then shows it to various people within the time period, including Charles-Gaspard de la Rive, who says that it might belong to Faraday, and Sarah Barnard, who says that she only needs the "magnetic personality" of her husband, Michael Faraday. Eventually, Mario confirms that the Magnet belongs to Faraday and presents it to him as he is in the middle of experimenting. Faraday then thanks Mario and immediately puts it to use in his experiment, confirming his theories.