Small nocturnal mammal (subfamily Erinaceinae) covered in spines that rolls into a ball for defense

to cluster together like the quills of a hedgehog; used to describe a large number of tasks or matters crowded together

to recoil or flinch in fear like a hedgehog curling up; to shrink back

(literary) to spring up like a hedgehog's spines; to arise in great numbers, specifically describing troubles, rumors, or events appearing everywhere at once