Why did my iPhone beep and say “scanning your device”

Sounds like an ad that was popped up by the game that you were playing. The developer of the game is payed to bring that ad to you. Many times these ads will attempt to scare you by claiming you have a virus by scanning your device.

Because you have money or metadata, and somebody wants it, and they decided to scare you to try to get your money or your data.

Words like HACKER! and VIRUS! can open wallets all over, and fear routinely gets some unnecessary and sketchy apps installed. Recipients are encouraged to DO SOMETHING! (The recommended “something” can be difficult to distinguish from malware, too. If not actually malware. Add-on “coffee shop” VPNs are an example of badly solving a problem that hasn’t existed for a decade or so, but badly solving it in a way perfect for collecting personally-identified metadata.)

Games are increasingly monetized, advertised, gamified, metadata-collecting, morasses of dark patterns, too. (The subset of games available in Apple Arcade games tend to have less of the badness that is permeating too many of the other games.)

The ad networks can also be a mess of sketchy ads, and add-on anti-malware can itself be problematic.

Here? That’s an audio file being served by the game itself or by an advertiser via an ad network, and with deliberately-scary sketchy content tagging. Not a hack. Not malware.

TamCatC wrote:

I was playing a game

sounds like you game was “scanning your device” in-app ad or sketchy advertisement(?)

ref: Why did my iPhone beep and say “scanning … - Apple Community

if you are using third party Anti-virus on this iPhone — uninstall it.

If you are using third party VPN try disabling it.

Recognize and avoid social engineering schemes including phishing messages, phony support calls, and other scams - Apple Support