- You may be looking for the Nebula-class of starship.
A nebula is an interstellar cloud of matter, usually gases (such as hydrogen) and dust. Many nebulae are stellar nurseries.
Since sensors and other systems functioned poorly in some nebulae, they were often used by starships to strategic advantage in conflicts.
The USS Enterprise-D hid inside a nebula from a Borg cube, temporarily shielding them from the Borg sensors. (TNG: "The Best of Both Worlds")
In 2371, Tom Riker took the hijacked USS Defiant into a nebula after Major Kira sabotaged the ship and temporarily rendered its cloaking device ineffective. (DS9: "Defiant")
Captain Ransom once hid from a Klingon Bird-of-Prey for three days in a nebula near Epsilon IV. (VOY: "Equinox, Part II")
In 2376, USS Equinox crewmember Maxwell Burke suggested taking the ship into a class 2 nebula in order to avoid the pursuing USS Voyager. (VOY: "Equinox, Part II")
While Voyager was undergoing a maintenance overhaul in 2377, the Delta Flyer II searched a nebula near Annari space for dilithium. (VOY: "Nightingale")
Later that year, a ship crewed by Hirogen prey holograms, led by Iden, hid from two Hirogen Venatic-class hunting vessels inside a nebula. In response, the Hirogen Alpha ordered one of his ships to circle the nebula, while the other entered it to drive the holograms out. Iden eventually left the nebula on his own to "liberate" three holograms on a nearby Nuu'Bari mining vessel. (VOY: "Flesh and Blood")
When the Voyager crew was forced to abandon ship due to tetryon radiation from a subspace mine in 2377, The Doctor, as the ECH, took the ship into a nebula to escape Quarren marauders. (VOY: "Workforce")