Bum shilling for animated character who’s lost his trousers (9)

I believe the answer is:

spongebob

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'animated character who's lost his trousers' is the definition.
The definition suggests a singular noun which matches the answer.

'bum shilling' is the wordplay.
'bum' becomes 'sponge' ('sponge' can be a synonym of 'bum').
'shilling' becomes 'bob'.
'sponge'+'bob'='SPONGEBOB'

'for' is the link.

Can you help me to learn more?

(Another definition for spongebob that I've seen is " Animated character".)

I've seen this clue in The Independent.

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