The Chaser - also known as Bad Dad or The Yeti - is the main antagonist of Dreaming Mary. He is first encountered in The Nightmare Realm of the dream, and is often interpereted as Mary's Father, who is also heavily implied to have sexually abused her.
The Chaser, at first, appears to be a tall, black, slimey monster with no visible body structure or facial features.
However, when he catches you, he clearly posesses a face with a frightening ear-to-ear grin complete with large, sharp teeth. There are no visible eyes in his sockets, leaving them to appear black and empty. Other than that, not much can be said about his looks, as most of it is blurred out by static.
Fast compared to Mary's walk, but much slower compared to how quickly she runs. The Chaser will, of course, begin to chase you when you enter the hall of the Nightmare Realm after you've collected 3 seeds. He is relentless, following you into the Nightmare Bedroom after escaping the Hallway, and even following you into other areas. If you try to open the door that requires 3 keys without having said keys, The Chaser will get you, slowly but surely. After attempting to open the door, there is no escaping from this.