the.com/sitting duck

means Someone or something left exposed and unable to escape an obvious, imminent attack or misfortune.

from Pulled straight from the hunter's pond: a duck floating still on the water is a far easier shot than one flying, so wildfowlers prized the bird that just sat there. The phrase paddled ashore into English by the early-to-mid 20th century, first in American usage, to describe any person or position caught helplessly out in the open — no cover, no escape, just waiting to be hit.