Grumpy is the name of a dinosaur character featured in the original 1974-1976 children's television series Land of the Lost, as well as the 2009 feature film remake of Land of the Lost. The original Grumpy character was made possible by way of stop-motion animation, whereas the film version of the animal was rendered through computer graphic imaging.
Grumpy was a Tyrannosaurus Rex and one of many reptile inhabitants of the "Lost Land" known as Altrusia. Though there were likely more Tyrannosaurs found in this strange world, Grumpy seems to be the only one who ever venture near the areas of High Bluff or the ancient ruins of the lost Sleestak city.
Grumpy was the first creature encountered by the spatially displaced travelers, Rick Marshall, Will Marshall, and Holly Marshall. Awakening inside their raft after falling through a dimensional rift, they were greeted by the thunderous roar of a large dinosaur. They fled from the area and the T-Rex pursued them. Fortunately, they were able to climb a bluff and take up shelter inside of a cave where the animal could not reach them. After several unsuccessful attempts to procure a meal, the dinosaur wandered off. It was Holly Marshall who gave him the nickname "Grumpy".
In addition to always searching for slow-moving humans or even slower-moving Pakuni, Grumpy also enjoyed engaging in battle with another dinosaur, an Allosaurus named Big Alice. The two would often square off against one another either in the ruins of the Lost City, or on either side of a large ravine.