Doomsday is the 3rd episode of animal Armageddon. It focuses on the first 24 hours of the extinction of the dinosaurs.
A not very big asteroid hits Alaska, killing some dinosaurs. However that was nothing compared to an asteroid the size of MT Everest that will hit the earth. Earth's inhabitants did not notice anything strange. An Edmontosaurus is feeding when two Troodon attacks. the Edmontosaurus was about to killed by a Troodon, when a Tyrannosaurus Rex attack the Troodon, sending them packing. The T-rex kills the Edmontosaurus and begins to chow down on it, completely unaware about the danger coming to him. The Phobosuchus and Mosasaurs are also eating the prey they killed, but the meteor is heading to them. The asteroid hits the Yucatan peninsula, starting doomsday. The dinosaurs nearby get incinerated with the mammals and insects going into hiding. Within 5 minutes it hits Texas causing Phobosuchus and nearby hadrosaurs to go extinct. Farther away T-rex, Triceratops and Edmontosaurus then gets hit by earthquakes, not extincting them, but causing them to struggle to get up. Later meteor fragments rains on earth, killing several dinosaurs and causing the pterosaurs to have holes in their wings. Just less then 6 hours, tsunami's become common, drowning dinosaurs living in the west African cost. The dinosaurs in Mongolia did not feel much effects, but that changed when a sandstorm shows up and burying dinosaurs alive. Meanwhile fires become common in America and Europe. For the full year of the dinosaur extinction see Panic in the sky