Yep, slugs were made for shotguns. And no, not a stupid question- some version of it gets asked here a lot.
Smoothbore uses a rifled slug. Rifled shotguns use sabot slugs. You will probably get best accuracy out of something OTHER than full choke. Would NOT shoot a slug thru an Extra Full, like turkey hunters use, but cylinder to full is OK.
Rifled slugs are slightly undersized, are very soft lead, big hollow inside, and the rifling on the outside of the slug is to allow it to squeeze down a bit if fired thru a choke.
What we have heah is.... failure to communicate.