The 3DO Blaster was an add-on produced by Creative Labs and designed to allow compatible Windows-based PCs to play games for the 3DO console.
It was a full-sized ISA compatibility card, and unlike other such add-ons, it does not emulate a 3DO system, but rather the whole system's logic board is included, with the input (controllers) and output (video & audio) redirected to the PC.
The product was marketed as a single board for CD-ROM drive owners (but only of a particular CD-ROM drive model, see below) or bundled with the necessary CD-ROM drive. The software drivers allowed for DOS or Windows (3.1) based gameplay, although Windows based gaming featured real-time stretching of the game window and screenshot capturing. As graphics boards of the time (1994) were not up to par with the system's needs, a pass-through using a VGA feature connector link was used, thus reserving an area on screen to be used by the 3DO Blaster card's output (on the Windows environment - running under DOS, full-screen was the only option). Thus, there was no impact on the CPU. As with the first 3DO system from Panasonic (REAL FZ-1) an FMV daughter-card enabling VideoCD playback was planned, but since the 3DO Blaster failed to achieve momentum, it was never released. Saved games were stored in NVRAM on the card, supposedly not using resources on the PC to prevent hacking.
Read more about 3DO Blaster: Required CD-ROM Drive, Bundle Contents, Hardware Requirements