It's the Eradica Titan, of the Advent Rebels.

The invincibility lasts for 2 minutes at level 6 and 4 minutes at level 8.

The invisibility is a bug.

This one eventually delved into the issue:

https://forums.sinsofasolarempire.com/424926/page/1/

I still think that when it goes invisible, the Eradica may possibly have more than 4 minutes of life.

 At level 6 the titan wiill spam chastic burst up to 24 times with a maxium yield of around 26,000 Damage points per sec. Around 11,000 dps after armor and mitigation.. if theres fracture abilities casting to some units well too bad for them.

[ rumor of a troll-not me ]With a level 8 eradica then its around a yield of 48,000 dps points per sec. Around 22,000 dps after mitigation and armor. With fracture casting.. cry me river. 

ps. if your a good advent player then you wont need this ability. 

Bingo, I still wish this ability were scrapped or changed into something else like user activated just less powerful. That and Purification and Strength of the Fallen at least having the same ranges.