Stinger or pincer's first to be grabbed by descendant (8)
I believe the answer is:
scorpion
'stinger' is the definition.
(I have seen 'Venomous stinger ' mean 'scorpion' so perhaps 'stinger' could also mean 'scorpion')
'or pincer's first to be grabbed by descendant' is the wordplay.
'pincer's first' becomes 'p' (1st letter of 'pincer').
'to be grabbed by' means one lot of letters goes inside another (inserted letters are grabbed inside).
'descendant' becomes 'scion' (scion is a kind of descendant).
'or'+'p'='orp'
'orp' placed within 'scion' is 'SCORPION'.
(Other definitions for scorpion that I've seen before include "Poisonous thing" , "Creature with a sting in its tail" , "Stinger with a long tail" , "Venemous creature" , "Small lobster-shaped animal" .)