Okay, now onto the juicy bits: how it mercilessly turns the PCs into paste.
I'm thinking the following, for a start:
Multiattack. The gurgohemoth can use its Frightful Presence. It then makes three attacks: one gore attack or one stomp attack together with two tail-lightning attacks or two different attacks from its tail and/or trunk (i.e. its tail, tail-flick and tail-lightning attacks or its trunk, trunk-crush, trunk-hurl and trunk-snort attacks, but it cannot use the same melee attack twice). An opponent attacked by the gurgohemoth's tail melee attacks cannot be targeted by gore or trunk attacks. Its tail and tail-flick can only be combined with a stomp attack or other attacks from its tail (its tail-lightning ranged attack can freely combine with other attacks).
Alternatively, the gurgohemoth can use Frightful Presence and then make two attacks: one gore and one stomp against separate opponents.
Gore. Melee Weapon Attack: +16 to hit, reach 20 ft., one target.
Hit: 42 (4d12 + 16) piercing damage.
Stomp. Melee Weapon Attack: +16 to hit, reach 10 ft., one creature that must be prone or Large size or smaller.
Hit: 42 (6d10 + 9) bludgeoning damage.
Frightful Presence. Each creature of the gurgohemoth's choice that is within 120 feet of the gurgohemoth and aware of it must succeed on a DC 16 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature’s saving throw is successful or the effect ends for it, the creature is immune to the gurgohemoth's Frightful Presence for the next 24 hours.
Tail. Melee Weapon Attack: +16 to hit, reach 20 ft., one target.
Hit: 21 (2d6 + 14) piercing damage.
Tail-Flick. Melee Weapon Attack: +16 to hit, reach 20 ft., one target.
Hit: No damage on hit, but target must make a DC 22 Dexterity or Strength saving throw (target's choice). The target takes 3 (d6) bludgeoning damage on a successful save, but on a failed save the target suffers the following:
If the target is Large size or smaller, they are thrown a distance of up to 30 ft. (6d6+9) in a random direction, or 15 ft. (2d8 + 6) for a Large creature. When the target hits the ground it takes 10 (3d6) falling (bludgeoning) damage and lands prone. If the gurgohemoth flicks its victim over a cliff or into a pit that also causes falling damage, the target takes whichever falling damage rolls higher (do not add the tail-flick's 3d6 falling damage to other falling damage).
If the target is Huge size or bigger, the tail knocks them over, the target takes 10 (3d6) falling (bludgeoning) damage and falls prone.
Tail-Lightning (As Ranged Attack). Ranged Weapon Attack: +14 to hit, range ??? ft., one target. Hit: 21 (6d6) lightning damage. Gurgohemoths and gurgotches are immune to this attack.
Tail-Lightning (As Save). The gurgohemoth's tail shoots black lightning at a single target within ??? ft. The target must make a DC 22 Dexterity saving throw, taking 21 (6d6) lightning damage on a failed save, or no damage on a successful one. Gurgohemoths and gurgotches are immune to this attack.
Not sure whether I prefer the save or the to hit version of this. I was going to add an AoE version of this as an option for Legendary Actions:
Forked Lightning. The gurgohemoth's tail shoots black lightning in a ???-foot line. Each creature in that area must make a DC 22 Dexterity saving throw, taking 21 (6d6) lightning damage on a failed save, or half as much damage on a successful one. Gurgohemoths and gurgotches are immune to this attack.
Trunk. Melee Weapon Attack: +16 to hit, reach 20 ft., one target.
Hit: 21 (4d6 + 7) bludgeoning damage and the target must make a DC 24 Dexterity or Strength saving throw (target's choice) or be grabbed (escape DC 24).
Trunk-Crush. Melee Weapon Attack: +16 to hit (can only target opponents that are grabbed and up to Huge size; automatically hits restrained targets), reach 20 ft., one target.
Hit: 21 (2d4 + 16) bludgeoning damage and the target is restrained.
Trunk-Hurl. Melee Weapon Attack: +16 to hit (automatically hits grabbed opponents), reach 20 ft., one target.
Hit: The target must make a DC 24 Dexterity or Strength saving throw (target's choice) or take 21 (4d6 + 7) bludgeoning (falling) damage, halved on a successful save. With a failed save the target also suffers the following:
If the target is Huge size or smaller, they are scooped up and hurled a distance of up to 40 ft. (8d6+8), or 20 ft. (4d6 + 6) for a Huge creature. The gurgohemoth can hurl the target in any direction and may throw them to land a shorter distance away than the listed maximum range if it desires. If the gurgohemoth hurls its victim over a cliff or into a pit that also causes falling damage, the target takes whichever falling damage rolls higher (do not add the trunk-toss's 4d6 + 7 falling damage to other falling damage).
If the target is Gargantuan size, the trunk sweeps their legs and slams them into the ground, causing them to fall prone.
Trunk-Snort. A bit of acid damage and maybe the poisoned condition for a few rounds? Gurgohemoths and gurgotches are immune to this attack.
The idea with the Trunk-Snort was the Gurgohemoth occasionally breathes out what to it is a small puff of gas which has the same effect as its breath weapon, albeit on a far reduced scale.
Haven't
quite decided on what effect I like for the Breath Weapon which means I couldn't qualify the Trunk-Snort either.
Maybe acid damage or necrotic damage?
Oh, I've already added the Gore and Stomp to the
Gurgohemoth, as they are pretty straightforward.