Trendy father switched a sum to an animal (12)
I believe the answer is:
hippopotamus
'an animal' is the definition.
(I've seen this before)
'trendy father switched a sum' is the wordplay.
I cannot really see how this works, but
'trendy' could be 'hip' (I've seen this in another clue) and 'hip' is found in the answer.
'father' could be 'pop' (pop is a kind of father) and 'pop' is found within the answer.
'a' is within the answer.
an anagram of 'sum' is 'mus' which is located in the answer.
The remaining letters 'ot' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'to' is the link.
Can you help me to learn more?
(Other definitions for hippopotamus that I've seen before include "River horse" , "African animal" , "Large aquatic beast" , "Creature" , "Large African mammal frequenting rivers" .)