Anyone Know Where Echo Is?

ya ive been searching all day for echo at perdition rock . cause i looked on map from xennon site and it says hydra with echo is there. so ive been searching where it spawns , its either a troll or a hydra with a diff elite skill.... no echo i cant figure out where it is. people have been saying its in the middle of the map and i went a couple of times and still no hydra with echo...

oops sry for ur time i just found out he only spawns at certain times. random times though so u got to zon in and out