Altogether popular animal in a fantasy film (2,4)

I believe the answer is:

in toto

I'm a little stuck... Click here to teach me more about this clue!

'altogether' is the definition.
(I've seen this before)

'popular animal in a fantasy film' is the wordplay.
'popular' becomes 'in' ('in' can mean trendy).
'animal in a fantasy film' becomes 'toto' (I can't justify this - if you can you should believe this answer much more).
'in'+'toto'='IN TOTO'

Can you help me to learn more?

(Other definitions for in toto that I've seen before include "All told" , "Completely - entirely (Latin)" , "Altogether, completely" , "In entirety" , "Tranquillity" .)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.