This is mine and mercies favorite map took me a bit to find the unit that shows them all but they show locations of hidden units. Also when we do duels the timer bugs out till we reset it. If this has already been report let me know.
#Duels Map
safe storm
native oak
Yes, the hidden units are special harmless entities present in all Duels maps. The game engine uses them for some Rules. Some day we will hide that buff so they are completely hidden.