Board Thread:Game Discussion/@comment-9713390-20130621174237/@comment-11029988-20130625003720

X1 and X2 are bosses that have stupid amounts of heath 1.5+ billion. Last event the X1 gave 20,000 xp and the X2 gave 40,000? Unlike normal bosses where only the seeder can call for help, anyone who participates can call for help, so there is a good chance of seeing them to boost.

What you should try and do is to use your level up cube refresh, (and use your hourly cube) to try and finish off a boss with only one cube thus "banking it" for future boss hits. Then rinse and repeat as much as possible. With the X1 and 2's coming soon, you will want to bank as many as possible if you can.