Tree house's second puppet (4)
I believe the answer is:
elmo
'puppet' is the definition.
I don't know anything about this answer so I cannot tell whether this works.
'tree house's second' is the wordplay.
'tree' becomes 'elm' (elm tree is a kind of tree).
'house's second' becomes 'o' (lnd letter of 'house').
'elm'+'o'='ELMO'
Can you help me to learn more?
(Other definitions for elmo that I've seen before include "Sesame Street character - patron saint of sailors (with his own fire)" , "St ...'s fire, weather phenomenon of coloured glow" , "Saint whose "fire" occurs around masts etc" , "St ----'s Fire: aura from electrical discharge" , "Saint whose fire is electric!" .)