It was an old Apocalypse conversion for the first release of Apocalypse back in 4th edition that
GW wrote up. A very "unofficial" type thing with no specific "this unit is available to X armies" type thing nor even what
FoC slot it takes (as Apocalypse doesn't care).
Purely from a background perspective, being exceedingly rare and originating with the Dark Angels, it being available to the Space Wolves would probably not be likely.
That said,
here's the rules for it.