Monster to walk slowly after beheading (5)
I believe the answer is:
troll
'monster' is the definition.
(I know that troll is a type of mythical creature)
'walk slowly after beheading' is the wordplay.
I cannot really understand how this works, but
'walk' could be 'roll' (roll is a kind of walk) and 'roll' is found within the answer.
A single letter 't' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
'to' is the link.
Can you help me to learn more?
(Other definitions for troll that I've seen before include "Grotesque dwarf" , "Ugly Norse dwarf" , "Fish - gnome - sing" , "Fish by drawing bait along in the water" , "Online annoyance" .)