Three warm years of constant rain. Rivers became lakes. The Green Ancients returned from under the earth finally able to withstand the environment. They soon learned about the humans who populated all over the area. They by there very nature cannot tolerate other intelligent beings to live. They began expanding there empires as fields became swamps and they attacked the farm houses on the new swamp's edges.
Uncle Jimmie Jake Thibes confronts the short squat Green Ancients that have suddenly shown up coming in from all the corners of the farm. He brandished a pitch fork as he tried to order them to leave. A low gurgling growl, as if plastic popping like frying bacon. They leap like great bullfrogs, the closest one jets out a claw swipe. Uncle plummets to the ground and a spray of his blood arcs and pulses and the others land and rend, strips of flesh and pieces of organs fly. The monsters are making vibrating keening high pitched sounds that make your skin hurt to hear it.
Most of the family was out doing chores and they witnessed about happened. Everyone scatters. The boy runs into the house for Pappy's shotgun. Greeners are scaling the farmhouse walls looking for a window to punch they're way into. They can make they're shells sticky to scale straight up things. They are bursting threw the window as the boy clicks the safety off and chambers a round. He blasts the closest greener point blank and the shell bursts open spraying a gory arc of green goo, still throbbing. The monster lays dead but the others are on the boy before he can pump the next shot ready. The horrid claws rip him apart. The goo oozing down the walls would curl your nose hairs.