how common is it for zoas to combine?

[smartwater101]

I've had some green button polyps and orange/brown for a year now. While setting up my new tank I noticed one polyp (in between the two colonies) has absorbed some of the green.

Its pretty neat albeit only one polyp. Is it common for them to morph like this?

 

[organism]

I've seen it happen when Palys grow into each other, not super common but not rare either. Makes for some nice color combos

 

[reepher315]

Looks like im gonna get some new paly colors