I'm homebrewing a creature that has the ability to summon things that buff its attacks and gives it resistances/immunities. The stat block is shown below.


Huge monstrosity, unaligned

Armor Class 17 (Natural Armor)

Hit Points 261 (18d12 + 144)

Speed 15 ft.

STR 24 (+7) DEX 10 (+0) CON 26 (+8) INT 3 (-4) WIS 10 (+0) CHA 7 (-2)

Saving Throws STR +14, CON +15

Skills Intimidation +17, Perception +14

Damage Immunities Poison

Condition Immunities Blinded, Deafened, Frightened, Poisoned

Senses Darkvision 60ft., Passive Perception 14

Languages --

Estimated CR 24

Fungal Body. The toadstool can’t be blinded, deafened, frightened, or poisoned, and any critical hit against it counts as a normal hit, unless it is incapacitated.

Buff. The toadstool becomes more powerful depending on the number of sporecaps summoned, as seen below.

1-4: The toadstool deals an extra 1d10 poison damage on all attacks, it can release an extra boomshroom.

5-7: The toadstool deals an extra 2d10 poison damage on attacks, it gains resistance to all damage from piercing, slashing, & bludgeoning damage from nonmagical attacks, and it can release an extra 2 boomshrooms.

8+: The toadstool deals an extra 3d10 poison damage on attacks, it gains immunity to all damage from piercing, slashing, & bludgeoning damage from nonmagical attacks, resistance to all damage from piercing, slashing, & bludgeoning damage from magical attacks, and it can release an extra 3 boomshrooms.


Multiattack. The toadstool makes two attacks, one with its bite and one other action.

Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., 1 target. Hit: 23 (3d10+ 7) piercing damage.

Sporecap. (Recharge 4-6) The toadstool summons 1d4 sporecaps, which are large, tree-size mushrooms. The sporecaps buff the toadstool. The number of sporecaps determines how powerful the toadstool is. These sporecaps have 5 (1d10) hit points each.

Boomshroom. The toadstool releases 4 (1d8) Boomshrooms. Boomshrooms are small mushrooms that grow and explode, and any creature within 5 feet of it takes 12(2d12) poison damage.

Spore Bomb. The toadstool attaches a spore to a creature of its choice within 20 feet of it. This spore explodes at the end of the target's next turn, creating a 5-ft square of poisonous gas for 1 minute. Anyone who enters the space of the cloud takes 13 (3d8) poison damage for each round they spend their turn inside the gas.

Ground Pound. When at 40% of it's max HP or less, the toadstool can hop on the ground, and any creature within 25 feet of it must succeed on a DC 15 Dexterity saving throw, taking 27(3d12+7) bludgeoning damage on a failed save, or half as much on a successful one.

How would the buff ability affect challenge rating?

  • 5
    \$\begingroup\$ @BenHess apologies for this much back and forth, there's a bunch of edits on this question and we're going to sort it out. I'm going to start a meta thread for this so it can be properly addressed. FWIW, this isn't a bad question, but I think something went awry procedurally. How do we address edits to a question that invalidate answers, which were based upon key information not provided by the querent? \$\endgroup\$ Mar 3, 2020 at 23:00
  • \$\begingroup\$ Comments are not for extended discussion; this conversation has been moved to chat. Please resolve any further issues with the question in the linked meta and/or in chat before continuing to further revert each other's edits. I've locked the question for a day in the meantime to allow that discussion to take place and resolve. \$\endgroup\$
    – V2Blast
    Mar 4, 2020 at 4:02

1 Answer 1


Most likely not at all.

That's because you are severely overestimating how long these 5 hp Sporecaps are sticking around. With a 50/50 recharge, let's assume that it is able to summon Sporecaps every other turn. It summons on average 2.5 spore rooms. Let's be generous and say it summons 3 on average, every 2 turns. To do this, it sacrifices a different action, which lowers its overall damage.

You're trying to aim for a CR24 creature, so we're looking at adventurers of what... level 18+ here who are going to be facing this enemy?

It might be able to get to the 5-7 range once, and as long as you properly narrate that the creature seems to be getting stronger because of the mushrooms, your players will figure out what is going on and from that point on, don't expect it to ever be able to get past 4 mushrooms. It can't make more than 4 in a turn, and killing 4 tree-sized objects with 5 HP each is absolutely trivial at that level, so the best it can do is make 1d4 of them and then attack with a bite, unless the order listed in the multi-attack is mandatory and it has to bite first and then summon mushrooms, in which case, the most optimal strategy for it is to just never use those mushrooms at all and instead go for boomshrooms.

Which is where your real problem for CR lies. You really, really should mention there that a creature can only be hit once by a boomshroom in any given action, else your 1d8 boomshrooms means that a creature can take anywhere from 2d12 to 16d12 damage if it simply spawns them all around a single target, which is ludicrously random.

That said, I'm not sure how you've gotten to CR24 in the first place. This is Ancient Red Dragon level, yet this creature has half the HP of an Ancient Red Dragon, +10 to hit less, 5 AC less, garbage saving throws on any spell that really matters and overall less reliable damage. I wager that 9 out of 10 times against a competent level 10+ party, this thing will never get a turn in because it will be moving last and spend the rest of the fight trying to make a DC 16+ saving throw against Hold Monster with its garbage +0 save.

And then you get to the real problem of this beasty, it's beaten entirely by a ranged character with poison immunity. A Periapt of Proof against Poison on a ranger means that ranger can take this thing down without ever getting in bite range. I really think you need to recalculate your creature's challenge rating.

  • \$\begingroup\$ did i fix it? how would the buff effect the CR now? \$\endgroup\$
    – Ben Hess
    Mar 3, 2020 at 17:55
  • \$\begingroup\$ This answer needs to be revised to consider the corrected hit points for the Sporecaps. \$\endgroup\$ Mar 3, 2020 at 18:00
  • \$\begingroup\$ Oh, I calculated that wrong? Thanks! \$\endgroup\$
    – Ben Hess
    Mar 3, 2020 at 18:06

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