A phrase used to urge someone/something on in a joking, mildly sarcastic manner. The implication is that what is being attempted is a trivial challenge, an obvious or already chosen course of action, or that the person is excessively frantic or exerting too much effort relative to the task. When spoken at an animal or inanimate object, the implication is an expectation of something about to occur, usually humorous to observe. The phrase is always spoken with "get" in a low tone and "it" with raising tone and volume, sometimes drawn out.
1.) "Dude, you gonna make that traffic light?" "Get IT!"
2.) "Oh no! My bus will be here any minute!" / "Get IT!"
3.) (gritting teeth before exercising with obviously light weights) "Get IT!"
4.) (dog snarling, about to chase its own tail) "Get ITTT!"