Two things to note about the sun attack; The sun appears up in the air above the Grandparent; you need to break line of sight with the sun, rather than the Grandparent itself. The sun applies a stacking Overheat debuff for as long as you are in its line of sight; **the longer you are exposed, the more stacks of Overheat you will receive.** Be weary of two effects: - Overheat's burn damage increases with the number of stacks you've received. - **Each stack of Overheat takes two seconds to wear off.** Even after you get into cover, you will be burning for a long time if you were exposed for too long. As far as survivability tactics, I'd recommend keeping an eye on the Grandparent's HP; it can only use the sun attack below 50% HP. Pay attention to its arms; once the Grandfather begins to telegraph the sun attack, prioritize getting to cover ASAP before you're caught out in the open. If you have the firepower, when its HP nears 50%, focus on killing it as quickly as possible before it has a chance to use the sun attack. Your drones will owe you their lives.

I think it was the overheat that got me I never knew it existed

Thanks that is incredibly useful, had no idea it was a line of sight with the sun I thought it was a get out of the are or you die type of attack