Codex/Galactic History 50: Basilisk

The Galactic History 50: Basilisk codex entry is located within the Achievements:Datacrons section of a player's codex once it has been unlocked.

Codex entry
"This datacron holds unheard of power and knowledge collected by an ancient race. You access its power and discover writings which are clearly only one small piece of a massive galactic history:

Since their grueling campaign against the Nevoota, the Mandalorians had only grown in power, cutting a swathe through the galaxy in search of worthy opponents. When the Mandalorians besieged the planet Basilisk, the Basiliskans–reptilian droid-builders and legendary technologists–learned that the stories of Mandalorian battle prowess were true.

Realizing they couldn’t win even with Republic aid, the Basiliskans chemically poisoned their own world, hoping to take their conquerors with them. But the Mandalorians were victorious nonetheless, enslaving the Basiliskans and eventually turning them into mindless beasts of war.

More importantly, the Mandalorians captured many of the unique droids that the Basiliskans created. After this conquest, they were able to mass-produce the droids for themselves. Centuries later, the Mandalorians’ Basilisk war droids would become a legendary terror during the Mandalorian Wars."