woolly bear

noun3

1. •
   A larva of the species Pyrrharctia isabellaa of arctiid moths.
2. •
   (informal) A hairy caterpillar.

   • Caryae is not a woolly bear, but is quite as densely covered with hairs and crawls quite as fast as any woolly bear. — 1902
3. •
   (slang, historical) An explosive shell that gives out dense smoke when it bursts.

   • As Bourne came out, he could see shells exploding by the dump, with some shrapnel bursting, woolly-bears they called them, overhead. — 1929