Nightmare and Error

(Evening. The working day was slowly coming to an end..
*
Nightmare is Experiment 13, created by one of the scientists. Nightmare was very attractive in appearance. He had short black hair that covered his right eye. Cold turquoise eyes with vertical pupils. He had four tentacles made of mucus, which he could easily retract. Nightmare could change his shape.
Error was a scientist who easily found common ground with experts. Error was quite attractive in appearance. He had short black hair. The right iris of his eye was grayish, and the left was yellow with a blue center.
Nightmare and Error were the same age.*
Error was now calmly talking with his colleague, Nick, who was in charge of Experiment Thirteen (Experiment Thirteen is a clever, dangerous, and aggressive experiment that has killed many scientists... Error had never seen Nightmare before, due to the fact that Error had previously been in charge of other sectors of the lab. Nightmare, however, fell in love with him the first time he saw Error.)
"I imagined experiment number thirteen a little differently... And it's beautiful," Error said quietly to his colleague.