The light gun peripheral of Sega for the MegaDrive is called Menacer. It consist of three parts:
It was a response of Sega to the Nintendo Super Scope. The Menacer was announced at the CES of 1992. The release date was end 1992 and the introduction price was USD 59.99.
There was a six game cartridge included:
Here are some more photos:
Information:
https://en.wikipedia.org/wiki/Menacer
https://segaretro.org/Menacer