liustiku kulutaval toimel tekkinud, ebasümmeetrilise tilga kujulised, positiivsed, vaid mõne kuni 10 cm kõrgused liustiku liikumise suunas orienteeritud pisivormid, crag and tail (formations) is a small-scale (a few cm) asymmetric positive streamlined erosional glacier bedform of rock with a gentle stoss (upstream) side and plucking on the higher lee (downstream) side. Forming while the force of the glacier erodes the surrounding softer material, leaving the rocky block protruding from the surrounding terrain.