PHOTONIC LATICE

These beings are one of the strangest ever encountered by Aliens Starfleet. They live on a protostar, have a sentient brain, but are completely photonic genetically. When Voyager personnel beamed aboard a sample of the protostar, they accidentally brought aboard two of the beings. One of them went on a rampage, converting crew members into energy on the holodeck. The Doctor saved the day when he confronted the being and came to a peaceful solution. (Episode Heroes and demons)