Green’s Dictionary of Slang

rock spider n.

[in Aus. senses, in nursery rhyme ‘Little Miss Muffet’: ‘There came a big spider / And sat down beside her’]

1. (Aus., also spider) a thief who robs courting couples in parks or at the seaside when their attention is elsewhere.

[Aus]S.J. Baker in Sun. Herald (Sydney) 8 June 9/1: Detective Doyle [...] says that [...] a ‘rock spider’ is a thief who steals from the handbags of couples sitting or reclining in parks.
see sense 3.

2. (S.Afr.) an Afrikaner.

[SA] informant in DSAE (1996).
[UK]C. Hope Private Parts 81: ‘Rockspider.’ The beefy man acknowledged this traditional insult by switching into his native Afrikaans with a terrible oath about Hilton’s mother’s womb.
[SA]P. Slabolepszy Sat. Night at the Palace (1985) 19: Let the rock spiders go fight. It’s their bladdy country.
[SA]R. Malan My Traitor’s Heart (1991) 54: The tyranny of the rockspiders, crunchies, hairybacks, ropes and bloody Dutchmen [...] Afrikaners.
[SA]A. Lovejoy Acid Alex 17: The same kid taught me [...] all the words for Rockspiders – Crunchies, Hairybacks, Clutchplates, Planks, Ropes, Boneheads, Dutchmen – Afrikaners-vrot-bananas.
[SA]Sun. Times (S. Afr.) Lifestyle 27 Jan. 10: My mum got this new boyfriend: a real rock-spider. [...] He used to abuse us, not sexually but physically.
[SA]Mail and Guardian (Johannesburg) 17 May [Internet] ‘Those bloody rock-spiders,’ we Engelsmanne would shot.

3. (Aus., also spider) a sexual offender, usu. a paedophile or child molester.

[Aus]R. Aven-Bray Ridgey-Didge Oz Jack Lang 45: Spider Child molester – as in ‘Sat down beside her.’.
[Aus]Canberra Times (ACT) 8 Mar. 10/6: James Francis Murray, 40, and Frederick John Owens, 35, told him they had ‘knocked’ a rock spider — jail slang for a child molester.
OnLine Dict. of Playground Sl. [Internet] rock spider n. sexual offender – specifically against children.
[US]Allan & Burridge Forbidden Words 160: An Australian dysphemism for a paedophile is rock spider.
[Aus] L. Redhead ‘Grassed’ in Crime Factory: Hard Labour [ebook] At least I’m not like your rock-spider husband. Pushing drugs on little girls so I can get into their white cotton panties.