hedgehog

because urchin = hedgehog

Fun fact, urchin originally meant hedgehog, so this actually works. From Etymonline:

Urchin

c. 1300, irchoun, yrichon "hedgehog, small spiny mammal of the Old World," from Old North French *irechon (cognate with Picard irechon, Walloon ireson, Hainaut hirchon), from Old French herichun "hedgehog" (Modern French hérisson). This is formed with diminutive suffix -on + Vulgar Latin *hericionem, from Latin ericius "hedgehog." This is reconstructed to be an enlarged form of er, originally *her, from PIE root *ghers- "to bristle" (source also of Greek kheros "hedgehog;" see horror).

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