If the glacier behemoth moves at least 10 feet, it can then use this action to continue moving in a 40-foot line that is 15 feet wide. Each creature in this line must make a DC 17 Dexterity saving throw. On a failure, a creature takes 35 (10d6) bludgeoning damage and is knocked prone. On a success, a creature takes half the damage and isn't knocked prone. The glacier behemoth's movement along this line doesn't provoke opportunity attacks.