Matilda's magic not starting, backfires and smokes (10)

'smokes' is the definition.
The answer and definition can be both man-made objects as well as being plural nouns.
Perhaps they are linked in a way I don't understand?

'matilda's magic not starting backfires' is the wordplay.
'matilda' becomes 'setter' (I can't justify this - if you can you should believe this answer much more).
'not starting' means to remove the first letter.
'backfires' says the letters should be written backwards (I've seen 'backfired' mean this).
'magic' with its initial letter taken off is 'agic'.
'setter'+'agic'='setteragic'
'setteragic' backwards is 'CIGARETTES'.

'and' acts as a link.