Anyways I have this ground pounder and during the first monarch break I broke from the group, walked a fair distance from the action and looked up where the "helion" had retreated into its lair. It wasn't visible and the health was grayed out but I proceeded to launch a number of precise bombs up inside the "mouth" anyways, than detonated them all and watched close to 3000"or so" damage float up, over and over and over again.
I've done this on many occasions now experimentally, its hard to say if the bar is actually depleting necessarily since its just me those few times so maybe its a wasted effort..but if it indeed takes damage and others can testify It could be exploited maybe lolol

just an observation