Demon, Doom (5e Creature)
From D&D Wiki
Medium fiend (demon), chaotic evil
Saving Throws Con +6
Charge. If the demon moves at least 15 feet straight toward a target and then hits it with a bite attack on the same turn, the target must succeed on a DC 13 Strength saving throw or be knocked prone.
Mulitattack. The demon makes two bite attacks.
Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) piercing damage.
Demons are gorilla-sized, pink-skinned, muscular monsters with a huge, powerful mouth. They have bull-like horns, glowing golden eyes, and strong digitigrade legs with three-clawed feet. They are fast: a horde of charging demons can eviscerate a squad of marines within seconds.
Spectres are partially invisible demons. They are sometimes seen as a shimmering silhouette, and sometimes completely invisible except for their glowing eyes. Creatures that rely on sight have disadvantage on attack rolls to hit a spectre, and disadvantage on Wisdom (Perception) checks to notice one. A spectre has the same CR as a demon.