Wherein your humble scribe presents another new monster for Swords & Wizardry (Core Rules), the Dung Spider.
Dung Spiders are poisonous arachnids roughly the size of two large fists held together. They take their name from the unique way in which they lie in wait for prey. A dung spider curls its long legs in on itself and sits on the ground, appearing to be a small pile of animal feces, biding its time until some unfortunate creature passes close enough for it to strike. When a target comes within 10′ of the dung spider, it uncoils rapidly and launches itself at its victim. The first time a creature encounters a dung spider surprise is automatic. Any future encounters will also result in automatic surprise unless the victim is particularly wary of being attacked by a dung spider.
Dung Spider: HD 1; AC 6 ; Atk 1 bite (1d2 + poison); Move 12; Save 16; CL/XP 3/60; Special: lethal poison (+3 saving throw), automatic surprise.