(covers information from several alternate timelines)
A trans-dimensional being or trans-dimensional energy creature was a lifeform that originated from or existed in a trans-dimensional realm.
The Sphere-Builders, who lived within the trans-dimensional disturbance in the Delphic Expanse, were an example of a trans-dimensional species. (ENT: "Azati Prime", "Damage", "Zero Hour")
In 2380, a hostile transdimensional energy sphere appeared aboard the USS Cerritos, where it was promptly tackled and subdued by Ensign Beckett Mariner. Although Mariner released the creature after it created a new tricorder and power cell for her, the act of creating the aforementioned objects had weakened the being significantly. When it tried to attack Captain Carol Freeman, it flew onto her shirt, where it quickly dissipated. (LD: "Envoys")
The Alliance of synthetic life may have included artificial lifeforms from multiple universes. (PIC: "Et in Arcadia Ego, Part 1", "Et in Arcadia Ego, Part 2")