Damage Formulas For Monsters

[Xyrlove Woodsoul]

So I've been using a modified version of the new guidelines for monsters posted in July's erratta (same math), and it has been very successful for me and my group (Totally solved our grind issue). But the problem I have now, is trying to determine damage for certain monster attacks. For example, some monsters get to make 2 melee basic attacks for a given power. But the damage for a single attack would be too high for two attacks, at that calibre. Thus, I switched it so, if the monster makes one attack, then I use the single attack damage that is listed; and if the monster make two attacks with that same power, then I treat it (both attacks) as multiple attack damage. Firstly, I just want to know if that sounds reasonable?

But I run into other confounds too. For example, I'm currently trying to convert a hydra, and they get an At-will attack, Hydra Fury using 5+ basic attacks, and even multiple attack damage seems way too high, maybe. My Hydra is level 17, and is listed to do 2d8+10 w/ multiple attacks, so, I dunno. What kind of formula should I use to determine how much damage each of their basic attacks should do if it gets 5+ basic attacks? I have an idea how, but I really don't know how to equate possible missed attacks into the equation (or even if that should matter). So any help would be appreciated. I'm thinking, leave it as it already is, listed in MM? Or 1d10+8 each hit (I took the Hydra's level, and divided by its # of heads, then consulted the erratta).
Also, is there a hydra in MMIII?
Thanks.

 

[CovertOps]

It sounds like the problem you're having is with Elites and Solos. If that is the case then their base attack should do the same damage as a normal creature (L+8). So for example a bite from one of the heads of the Hydra at L17 should do ~25 damage which could be represented as 3d10 + 9 or 4d10 + 3. Basically anything that gets you in the ballpark with ~25. Since Solos and Elites are worth the same XP as more than one creature they have to have a way to keep their action economy in the same ballpark as their equivalent creature count. Since a solo counts as 5 creatures (the aforementioned Hydra) it needs to be able to do as much damage as 5 creatures on it's turn so it gets "Hydra Fury" which allows it to make ~5 such bite attacks, each of which does the same damage as a single standard monster of the same level. Make sense?

 

[Xyrlove Woodsoul]

That makes TOTAL sense, except for that I use the new damage expressions in July's Erratta, and that would make it 2d12+18 each attack, for 6 attacks (or more). That just seems like certain death for a character being attacked by a bunch of heads? 5 standard creatures wouldn't usually be able to focus fire like that. I guess I could dm it so it doesn't focus fire, but I don't like having to do that, necessarily. I suppose my problem is a shortcoming of the erratta: I mean, I tried to do it by the RAW (erratta-wise) for another creature (Skeletal Guardian, I do believe) who got 4 basic attacks, and they totally decimated everyone in the party, way beyond what the monster's level would indicate. But, like I said, the erratta has worked great for us (given our playstyle), it's just hard to convert certain attacks. I think I'm going to consult MMIII to get more of an idea. Thank you.