Amusing puppet grabbing alligator's tail (5)
I believe the answer is:
droll
'amusing' is the definition.
(thesaurus)
'puppet grabbing alligator's tail' is the wordplay.
'puppet' becomes 'doll' (I've seen this before**).
'grabbing' means one lot of letters goes inside another.
'tail' suggests the final letters.
The last letter of 'alligator' is 'r'.
'doll' going around 'r' is 'DROLL'.
(Other definitions for droll that I've seen before include "Funny" , "Quaintly amusing" , "Amusing - jester" , "Humorous or whimsical" , "Whimsical - amusing" .)