Animal quietly lying in ground (8)
I believe the answer is:
terrapin
'animal' is the definition.
The answer is an example.
'quietly lying in ground' is the wordplay.
'quietly' becomes 'p' (p for piano and quiet).
'lying in' indicates putting letters inside.
'ground' becomes 'terrain' (I've seen this before).
'p' inserted into 'terrain' is 'TERRAPIN'.
(Other definitions for terrapin that I've seen before include "Web-footed turtle" , "edible, freshwater reptile" , "freshwater creature" , "A reptile; a printer (anag.)" , "Swimmer" .)