Raging Massacre.   Due to the characters lack of insight and wisdom they will be punished by a barrage of attacks.All 3 heads will get to use their bite attacks, also the stop and tail attacks.

Fire Bite. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 33 (4d12 + 7) piercing damage plus 2d12 fire damage. If the target is a Medium or smaller creature, it is grappled (escape DC 17). Until this grapple ends, the target is restrained, and the tyrannosaurus can't bite another target. (only while on fire platform or on ground)

Poison Bite. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 33 (4d12 + 7) piercing damage plus 2d12 poison damage. If the target is a Medium or smaller creature, it is grappled (escape DC 17). Until this grapple ends, the target is restrained, and the tyrannosaurus can't bite another target. (Only while on poison platform or ground)

Smite Bite. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 33 (4d12 + 7) piercing damage plus 2d12 Holy damage. If the target is a Medium or smaller creature, it is grappled (escape DC 17). Until this grapple ends, the target is restrained, and the tyrannosaurus can't bite another target. (Only while on final platform or ground)

Tail. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 20 (3d8 + 7) bludgeoning.

Stomp.  Melee Weapon Attack:+20 to hit, reach 100 ft. radius from Zacama, all targets. Hit:30 (10d10) if anything lives it is prone and stunned.

Fire head: While one the fire platform, fire spells will be eaten up by a feather on the head, this feather will also flash before the head does any of it's moves, same for the main beast it will always go last.  So do a perception roll (passive 15) will pass and be able to tell it absorbing the fire element due to the flames near the edge of the platform seeping towards it.  After it makes it bite attack it will have 2 moves it can use, it can only use one of the moves each round

Fire Breath. Cone magic attack 3d6 fire damage, must make a dex (1d8+Zacama's dex) save throw to take half damage. 15ft cone.

Turn Up the Heat . Arena change Make the aura surrounding the platform become more intense, when players warp to platform it starts at level 1 each use of this ability will raise it by 1, at level 3 it becomes hard to fight and each player will have 1 level of exhaustion. Level 4 they will take 1d4 fire damage and 2 levels of exhaustion, level 5 1d12 and 3 levels of exhaustion, level 6 they are all burned to a crisp.  After this ability is used players can investigate and can tell they can lower this heat by targeting it with an ice/water spell, a cantrip will lower it by 1, level 1 spell can lower it by 2, and for each level higher than that will lower it an additional level.  Can not go below level 1.

Acid Head: While on this platform healing spells (potions will not trigger this) will target the head instead of the users, if it is a ground healing spell the head can gain it's benefits as if it started it's turn in the area.  Same rules for detection apply, a feather is absorbing, it just can't be destroyed.  Only has 1 ability that can be used on every 3rd round

Decay. Arena Change Roll 1d10 for each playing character, if a 1 is rolled their square decays and becomes unstable and collapses.  Warn player and let them have a reaction if this happens, they can jump off the platform to avoid taking fall damage from over 150 ft but will lose the ability to move on their next turn, and cannot react to enemy abilities.

Divine Head: The feather on this head will absorb any stat boosting spells/abilities except for rage (inspiration, haste, shield) as well as divine spells.  Will also cancel out any help from Divine deities.  The platform will have a random square glow, roll 2d6 1st number across, 2nd number down.  This is before any character goes, if someone stands on that square they will get Shield, and the ability to go twice, and inspiration or reduce the light aura by 1 level.  If no one stands on it the square will turn red and Tacama will get these abilities instead for one round.  If he gets 2 in a row, will gain resistance to all slashing/piercing/bludgeoning magical damage, and 1 random element  he will have 2 abilities that he can use either one at a time or twice.

Blinded By the Light rev up like a ****** arena change  The holy Aura surrounding the ring intensifies making it harder to see, but it also heals.  Level 1 head 1d4 on start of turn, and add 1d4 for each level after, starting at level 3 it is becoming hard to see -2 on all attack rolls, level 4 disadvantage on physical saves and attack rolls, level 5 they are absorbed into the light and will elevate to the holy plane to live out their lives.  This can be negated by the darkness spell, that will negate all healing as well but the light aura will be gone for the duration of the spell, once it is over it starts at level 1 again.

Arrows of Light aoe ranged attack Will rain down arrows of light from the heavens 2 will be a guaranteed hit and the other 5 will be random, roll 2d6 to determine where it will land.  Does 2d6+5 holy damage.