Look outside. Are pigs flying? Has hell frozen over? I ask because Microsoft just announced that it's bringing its Windows Defender antivirus software to the Mac.

Or, rather, the company is bringing Microsoft Defender to macOS, because Microsoft is rebranding the software as it takes Windows Defender beyond Windows (it's also apparently coming to Linux!). Currently available to business users in a preview version, Microsoft Defender will support macOS Mojave, macOS High Sierra and macOS Sierra machines.

Announced in a blog post today (March 21), Microsoft Defender scans for malware, with options for full scans, quick scans and scans of specific directories. In the blog post, Microsoft's Eric Avena states that "we recommend quick scans in nearly all scenarios."

The service's full name, Microsoft Defender ATP, stems from Microsoft's recent addition of "Advanced Threat Protection" tools for its Microsoft 365 customers, which added automation and cross-device and cross-identity functionality.

You can review the threats that Microsoft Defender finds, and the software will give you the option to quarantine the files, remove them entirely or let them continue to take up space. Advanced settings include real-time protection and cloud-based protection.

Other basics included will be the option to white-list directories to exclude them from scans, and to check for Microsoft's "security intelligence updates" automatically or manually.

Business users already using Windows Defender ATP can sign up for the Mac beta version, and even request a quotation on how much the full product will cost.

According to a different official blog post, Microsoft has roped in the support of antivirus and network-protection firms Bitdefender, Lookout, SentinelOne and Ziften to add some sort of unspecified protection to Android and iOS devices as well.

We expect this Mac antivirus software to exit this business-only preview at some point and become a full public release. Recently, Microsoft released Windows Defender Application Guard browser extensions for Google Chrome and Mozilla Firefox, so a wider release seems natural.

The consumer version of Windows Defender, built into all consumer versions of Windows 10, has caught up to the best paid antivirus programs in the most recent third-party lab tests. We're looking forward to finding out how Microsoft Defender for Mac does against third-party Mac antivirus software, and against Apple's built-in XProtect antivirus software.