A rest for Ronnie O’Sullivan? (6)

I believe the answer is:

spider

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

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

I don't understand the remainder of the clue.

(Other definitions for spider that I've seen before include "Harvester" , "Spinner" , "One has eight legs" , "Arthropod; snooker rest" , "Creator of web" .)

I've seen this clue in The Times.

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