Glowball was a Force technique invented by the Arcona Jedi Knight Izal Waz during the Yuuzhan Vong War.
To create a glowball, Waz would use the Force to gather ambient light into one location. The resulting phenomenon resembled a small star and could be used to hide ships in battle from the enemy. Early utilizations of the glowball completely drained Waz of his energy, causing physical collapse.
The first documented usage occurred at Arkania, where Waz hid the blastboat Jolly Man from the Yuuzhan Vong in an attempt to capture a yammosk.
The technique was later adopted by Mara Jade Skywalker and other Jedi, as well.