Well cooked crab I ate — it could make one sick (8)
I believe the answer is:
bacteria
'make one sick' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'well cooked crab i ate it' is the wordplay.
'crab i ate' anagrams to 'BACTERIA'.
Though, I am unsure how this is indicated.
'could' acts as a link.
Can you help me to learn more?
(Other definitions for bacteria that I've seen before include "Possible cause of disease" , "Micro-organisms, often pathogens" , "Germs or bugs" , "could make you feel bad" , "Microscopic organisms, good and bad" .)