Monster some sailor caught (3)

I believe the answer is:

orc

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

'monster' is the definition.
(fantasy creature)

'some sailor caught' is the wordplay.
'ORC' is hidden within the letters.
However, I am unsure how this is indicated.

Can you help me to learn more?

(Other definitions for orc that I've seen before include "Ugly creature" , "Fairytale monster" , "Tolkienian monster" , "Killer-whale" , "Imaginary creature" .)

I've seen this clue in The Times.

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