bubble corals?
 

I have two. I want to place them adjacent to each other. will there be a war between them, or can they co-exist next to each other?

All corals compete for space as in nature, placing two of the same species side by side is a gamble just the same as two different species. A coral prefers it's own space and cannot always differentiate between it's own species, so it will sting anything that intrudes on it's space. Bubble coral also have especially long stingers due to it's aggressive species, so i would be careful in placement of this coral no matter what coral is close by even if it's another bubble.