Creatures that ruin the marrows? (10)

I believe the answer is:

earthworms

'creatures' is the definition.
(earthworm is a kind of creature)

'ruin the marrows?' is the wordplay.
'ruin' is an anagram indicator.
'the'+'marrows'='themarrows'
'themarrows' with letters rearranged gives 'EARTHWORMS'.

'that' acts as a link.

(Another definition for earthworms that I've seen is " Creatures".)

I've seen this clue in The Telegraph.

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