Released in 1993, the Pioneer LaserActive was a laserdisc player which, through the use of expansion bays, was able to play games from the Sega Mega Drive (Genesis) and PC Engine (TurboGrafx-16). The expansion bays were known as PAC modules.
NEC PAC
One of the expansion modules released allowed it to play PC Engine titles (HuCards, CD-ROM2 and Super CD) as well as games released on laserdisc (LD-ROM2) that only worked on this setup. Eleven LD-ROM2 titles were released in Japan, though only three of them were released in North America.
The module came with a PC Engine controller which had a Pioneer LaserActive logo on it.
Sega PAC
The other popular module allowed you to play Sega CD and Sega Mega Drive (Genesis) games. It also let you play Mega LD discs, which were 8 or 12 inches in size. It came with a 6 button controller with the Pioneer LaserActive on it.
Apparently, this was a very popular module, in total 29 games were released for it.
Other Modules & Accessories
Other modules included the Karaoke PAC, which let you input a microphone for Karaoke songs; and the Computer PAC, which let you connect the player to a computer.
You could also purchase 3-D Goggles, which could be used for certain games or laserdiscs.
For more information on the Pioneer LaserActive, I recommend reading this article from Laser Disc Archive.