Sounds like sleep paralysis:
During an episode, the person may hallucinate (hear, feel, or see things that are not there), which often results in fear. [...] Sleep paralysis may include hallucinations, such as an intruding presence or dark figure in the room. These are commonly known as sleep paralysis demons. It may also include suffocating or the individual feeling a sense of terror, accompanied by a feeling of pressure on one's chest and difficulty breathing.