A little boy's terrified being swallowed alive (6)

I believe the answer is:

oyster

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

'swallowed alive' is the definition.
I can't tell whether this definition defines the answer.

'a little boy's terrified being' is the wordplay.
'a little' says the answer is hidden in the clue (a little bit of the clue).
'OYSTER' is hidden in the letters of 'boys terrified being'.

Can you help me to learn more?

(Other definitions for oyster that I've seen before include "Pearl-making mollusc" , "person unwilling to communicate" , "Flat shellfish" , "Shellfish - colour" , "Means to cross London" .)

I've seen this clue in The Independent.

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