Question

how did poet describe the snake

Answer 1

In the beginning, the snake moves slowly, the body is "slack": he "trailed" his body along. When he had drunk water, he moved as if "thrice a dream". This dreaming state was shattered by the poet who threw a log at the snake, making it move forward " in undignified haste", and making it writte 'like lightning', swiftly entering the whole in the ground. The poetic device used is Simile.

Answer 2

the poet describe the snake into a slack