Monster Making and CR

[Vahn Ardos]

I'm running a campaign for my group of three players, and since I couldn't find anything to represent my concept for a boss-type guy, I decided to make one. This is new, unexplored territory for me, but I statted him up and was pleased with the result. The only thing that's wrong is that he has no CR, I'm uncertain how much exp to give, and I'm not sure if a 3rd level party can triumph over him. Any tweaks/tips/comments you might have would be much appreciated!

I present to you, the Harvest King!

Large Plant
Hit Dice: 6d8+24
HP: 51
Initiative: +1
Speed: 40 ft. (8 squares)
AC: 20 (+1 Dex, -1 size, +10 natural), touch 10, flat-footed 19
Base Attack/Grapple: +4/+13
Attack: Gore +8 (2d6+5) or Slam +8 (1d6+5)
Full Attack: Gore +6 (2d6+2) and 2 Slams +8 (1d6+5)
Space/Reach: 10 ft./10 ft.
Special Attacks: Sow the Seeds, Reap What You Sow (1d4 damage, Fort DC 17 half)
Special Qualities: DR 5/magic or cold iron, Resist cold 10, electricity 10, acid 10, low-light vision, plant traits
Saves: Fort +9, Ref +3, Will +4
Abilities: Str 20, Dex 12, Con 18, Int 14, Wis 14, Cha 16
Skills: Hide +6 (+16 in forested areas), Listen +11, Move Silently +6, Sense Motive +6, Spot +11
Feats: Improved Natural Attack (Gore), Multiattack, Iron Will
Alignment: Neutral Evil

Sow the Seeds (Su): As a swift action, the Harvest King can throw out a cloud of seeds in a 15 ft. cone. Living creatures caught in this cone take 1 point of damage as the seeds burrow into flesh and begin to take root. They are also considered seeded and eligible targets for the Harvest King's Reap What You Sow ability. Removing the seeds takes a full-round action and a DC 20 Heal check. A Neutralize Poison spell will remove the seeds as well. Once the Harvest King uses this ability, it can't use it again until 1d4+1 rounds later.

Reap What You Sow (Su): As a swift action, the Harvest King can draw sustenance from living creatures. Any seeded creatures within 30 ft. of the Harvest King take 1d4 damage (Fortitude save DC 17 for half damage) and the Harvest King is healed half of the total damage dealt. Those creatures are no longer considered seeded.

[Zexion]

If you want this to be a good encounter for 3rd level characters, you should probably tone down the AC. In the DMG, a natural armor bonus of +10 is described as "extremely thick hide, similar to a rhino's," which I'm pretty sure this is not. Also, a 3rd level fighter has a BAB of +3, and would have to roll a 17 or higher to hit this monstrosity. I repeat: tone down the AC. Otherwise, this is CR 4 or 5.

[DracoDei]

Also, a 3rd level fighter has a BAB of +3, and would have to roll a 17 or higher to hit this monstrosity. I repeat: tone down the AC. Otherwise, this is CR 4 or 5.

He also adds his strength modifier, and if he isn't getting at least +1 from some sort of supernatural effect (magic weapon, bard song, etc) then the party may be doing something wrong. I don't know if toning it down is or is not indicated, but it the situation is not quite as dire as you seem to think it is.

[Altair_the_Vexed]

Vorpal Tribble made this handy thread for monster making, in which he laid out some guidelines for working out a CR.

[The Vorpal Tribble]

Vorpal Tribble made this handy thread for monster making, in which he laid out some guidelines for working out a CR.

Yeah, looks to be a tough 5 or an easy 6.