Lion perhaps a pet? That leads to explosive disaster (11)
I believe the answer is:
catastrophe
'disaster' is the definition.
(synonyms)
'lion perhaps a pet? that leads to explosive' is the wordplay.
'lion perhaps' becomes 'cat' (lions are big cats).
'pet?' becomes 'strop' (both can mean a tantrum).
'that leads to' is a charade indicator (letters next to each other).
'explosive' becomes 'he' (abbreviation for high explosive).
'cat'+'a'+'strop'+'he'='CATASTROPHE'
(Other definitions for catastrophe that I've seen before include "Great disaster" , "Calamity" , "Denouement" , "Event causing great suffering" , "Tragedy" .)