Comments posted to our Dark Souls 3 Wiki
My Irithyll Straightsword +5 (frost) deals more damage to these guys than my Chaos Longsword +10 (fire.) I have the right attributes for each sword mentioned. -Mikko
Sometimes they will drag you down to beset you.

Floor Draggers:
If your HP goes to 0 with this grab, you will be fully dragged down underground, so the Murkmen will beset you more.