Created due to a defensive measure within the AGES cells, Nightmare is a horrific example of a failed attempt of retro engineering the AGES Virus. Standing about twelve feet tall, Nightmare is a grotesque creation taking a vaguely human shape with random limbs and organs growing out of the central mass. Despite it's largely hodge podge shape, Nightmare proved to be a devastating monster, capable of jumping long distances and running at a good clip.
Nightmare is an example of false replication and largely a cancerous form of AGES developed in this process. Initially injected with the prototype AGES virus, the subject appeared to have Tyrant like capabilities: enhanced strength, durability and vitality but quickly things went out of control. Normally AGES and Zeus cells produce a hormone that largely suppresses the immune system so that the "foreign" cells can completely convert the normal cells in the body. Due to the mistake in the prototype virus being linked to Alex Isaacs, these cells were still detected by the immune system and they attacked them. This causes the AGES cells to begin to defend themselves by attacking the body. In this, the infection is at the point where the AGES cells are largely the dominant cells of the body. Through this, the AGES cells attempt to rebuild the damage, but due to the incomplete infection, the cells don't know what to build, and thus produces random parts of the body in out of place areas.
Examples of this is that the "head" is in the abdomen of the original host, who is now ripped in half due to the mutations. The legs are made out of several limbs fused together and the left features a random spinal column and a skull. The left arm features a secondary mouth that doubles as its "reproductive track" and ends above where the elbow should be, the arms ends an eye.
Nightmare reproduced several "Night Terror" children. These resembled a human torso with an eye where the legs should attach and the head section is where an mouth has developed. These walk on two normally formed legs where the arms should be.
Nightmare and it's children, Night Terrors, were ultimately killed in the events before the Orlando Outbreak.