The VwNM boss Vanasarvik in Mount Zhayolm kept disappearing into the ground every few seconds, causing the Elder's Imps to go nuts on the entire alliance and resulting in a wipe. This took place on 22/07/2013 at 23:55 GMT on Leviathan server. This didn't happen the previous times we fought it so it completely took us by surprise and there was nothing we could do about it. It meant every time it disappeared all our abilities were cancelled due to it being "out of range" and the imps would then start spreading out randomly hitting the rest of the alliance.