Attempt something risky and Merman's impaled by stingray's tail (3,2,2)
I believe the answer is:
try it on
'merman's impaled by stingray's tail' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'attempt something risky and' is the wordplay.
I cannot really see how this works, but
'attempt' could be 'try' (synonyms) and 'try' is found within the answer.
'something' could be 'it' (I've seen this in other clues) and 'it' is present in the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is found within the answer.
A single letter 'o' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for try it on that I've seen before include "When buying new suit one should" , "Attempt to get away with something" , "practise a little deception" , "See how far one can push things" , "Aim to deceive" .)