LIke frogspawn, they're euphyllia species, and will even coexist at close range with frog. They're not bad about sweepers, are tolerant of most things except low alkalinity.
This retraction reaction is particularly strong in a euphyllia that's not long in its current position. They seem to get 'nervous.'...or at least their hazard sensor is stuck in 'on' position.
They like a chaotic moderate current and mine doesn't mind mh lighting at fairly close range: the lighting option seems variable for them.
They don't 'eat' as obviously as other lps; letting cyclopeeze float in the tank is probably the best food.