From Wookieepedia, the Star Wars wiki.
The Battle of Tynna during the Yuuzhan Vong War was not fought for a specific strategic target. Rather, the Vong launched the attack in an attempt to ensure that the New Republic believed their captured intelligence that the next Vong attack would be either Corellia or Bothawui. The Vong hoped that the New Republic would deplete their forces protecting both planets, when they actually planned to attack Fondor next.
During the battle, the Vong captured the Tanallay Surge complex and used it to release a biotoxin into Tynna's world-sea. It quickly made the ocean deadly to any non-Vong lifeforms, thus aiding in both their conquest and terraforming of the planet.
- Agents of Chaos II: Jedi Eclipse (First appearance)
- Force Heretic II: Refugee (Mentioned only)