In Mercenaries Mode (current game build 29.6.2.202360.201392),
After selecting the treasure Hunting Party (Rank 3) for Rexxar: Passive: Your beasts have +4 Attack. Whenever an enemy minion is summoned, destroy it.
The treasure is not destroying summoned enemy minions.
I recently fought in the Balinda Stonehearth Bounty (Normal, I believe) in Alterac Valley, and she summoned Lesser Water Elemental while Rexxar was on the field with the selected treasure, but the treasure did not destroy the Lesser Elemental on summoning.
Afterwards, I completed the Chromaggus Bounty (Normal) in Blackrock Mountain, also with Rexxar on the field using the Hunting Party treasure. During the fight, Chromaggus used Chromatic Call and summoned two Chromatic Drakes to the field, which the treasure also failed to destroy.
While I hadn’t played Mercenaries mode in a few months, I believe this treasure was not working last time I played this mode as well.
I am unsure if the treasure is only not working against the final boss’s summons in the final boss fight on bounty tracks, or if the treasure is also not working against regular minions’ summons during earlier fights along bounty tracks.
If memory serves, it has a colour and is a merc, right? (UPD: It has and it is) In this case, see this old explanation (and a bunch of links there):
Yep, these too have roles and thus are mercs (you can also distinguish a minion, e.g. from a neutral merc, i.e. one without a role and also grey, by its border, I think).
I’m quite sure it still works the same way as when those old posts were written.
In short, Hunting Party is supposed to destroy summoned enemy minions, not mercs.
Hate to break it for you, but it’s probably all irrelevant.
Chromaggus — you could burn it down with something like a Nature team (Malfurion-Nemsy-Brukan would probably be the modern version) or a Frost team in the form of Balinda (with a lesser water elemental), Varden (band of frost) and Lokholar (Icy Focus is probably better for the boss, Frigid Winds are generally useful — you might as well not bother and roll with these). If memory serves, it has never been one of the more difficult bosses.
Balinda — you could use something like a Holy team (Xyrella/Cornelius, Velen, Anduin etc), but a super-star for this bounty in particular is Chi-Ji, bonus points if you also have some ‘tokens’ (minions) on the board. You see, every second turn Balinda will do the ‘Uncouth scum!’ manoeuvre, reducing the health of you characters to 1 but giving each of them a lot of heal power. Obviously, you want some kind of healing vs this boss, and many solutions can work (Fire is okay too with Chi-Ji), but the aforementioned boss’s skill (called ‘Crestfallen rebuke’ or something like it) synergises particularly well with your Chi-Ji (and if you have any additional minions, they get even more healing power), resulting in massive Firestorms (it doesn’t even matter if your Chi-Ji’s skills aren’t upgraded much), which can essentially clear the boss by itself.
PS Rexxar is quite strong in a Beast party together with mercenaries like Trigore, Mukla, Xuen, Anacondra… But maybe not versus Balinda , although, come to think of it, if you also add Ch-Ji, it should be quite strong: Anacondra summons the viper with her ring, Rexxar can just summon Misha turn 1 and so on, so there are a lot of tokens for Chi-Ji.
