Super glue won't work for xenia at all. If you haven't tried it already, you will see that it is too slimy for glue to work. A rubber band will work fine, it should take hold in a day or two and then you can remove the rubberband.
option 1: black thread, sewing needle, needle black thread thru the base of the xenia & then tie down tightly to rock
option 2: if you have enough stalk on the xenia, put rubberband around the rock, take the base of the stalk & "pinch-it" underneath the rubberband.
i'm not a big fan of superglue as all "softie" coral have a slime they build-up & they will work that slime in between itself & the superglue. in 2 days you most likely have a rock with superglue on it & your xenia floating around inside the tank somewhere. coral must have complete contact with the rock naturally & no foreign-substance like super-glue in between the coral & the rock. glue has never worked for me with any type of "softie" coral.
place rock in a very low flow part of the tank. either way...allow 3-5 days for the xenia to grab hold if you use option 1 or 2 above
I put a rubber band on it. It's not coming out at all. I shut the light off for the night so I guess we'll see what happens tomorrow. My peppermint shrimp keeps on messing with it. He keeps it up I might have to feed him to my stars and strip puffer in my other tank. j/k :rotflmao: thanks for the help