Mark this beat (6)
I believe the answer is:
tattoo
This clue is a double definition.
'mark' is the first definition.
(thesaurus)
'this beat' is the second definition.
(thesaurus)
(Other definitions for tattoo that I've seen before include "drawing on arms, perhaps" , "Skin decoration; drum signal" , "Indelible marks drawn on the skin" , "paraded?" , "Skin design - military entertainment" .)