Hey everyone!

I wanted to share my door puzzle trap encounter with everyone on the board. Maybe I can get some tips from you or you just might want to steal the idea. Either way, here is my idea.

Garaslix' door of doom

Description
A group of adventurers is about to stumble upon a closed doorway with two big metal double doors. When they first lay eyes upon it, they see that the door is in good shape. It's not old and corroded, yet it seems to be here for quite a while. It also does not have any handles. The doorway is rectangular in shape, like most normal doors. Connected to the top of the doorway is a flat semicircle plate, made out ot the same metal. It is just as wide as the doorway. Around the edge of the semicircle is an arch. The players can make an easy perception check to see the arch has seven recesses in it. Below the arc, in the middle of the semicircle is a shape that's actually the head of a creature. The players can make a suitable check (I would say it's arcana or history) to recognize the creature. If they succeed they would recognize an aboleth. There's three black eyes just below each other, staring at the players.

Guardian
To make it more interesting, a door guardian pops from the ceiling if the players touch the door or get very close to it. The guardian is a spectator. He is guarding the door for his master, the aboleth. He has instructions to keep nosy people out of the room that lies beyond the door. His solitude has made him a bit mad however. He will introduce himself and ask if they are followers of his master. If the players manage to fool him or convince him, he will give them five minutes to open the door. If they don't open it within those five minutes, he will attack. If it's clear that they are not supposed to be in there, the guardian will give them one warning to stay away, or he will attack.

Details
If a player succesfully investigates the door, he or she knows that the door is rigged with traps, that will go off if they do something wrong. Investigating this hallway reveals a false wall, where a small wooden box sits behind it. The box contains seven colored gems. A succesful check reveals what kind of gems they are, if a player wants to investigate them.
The seven gems:
Red gem (Ruby) DC 5 check
Black gem (Onyx) DC 10 check
Multi-colored gem (Yowah nut) DC 20 check
Transparent gem (Goshenite) DC 15 check
Yellow gem (Beryl) DC 10 check
Blue gem (Iolite) DC 15 check
Green gem (Variscite) DC 15 check

The players might make a connection between the recesses in the arch, and the gems. The gems have to placed in those recesses in a specific order. If they make a mistake placing them, a trap will go off.
The trap will fire a bolt of energy from the bottom eye of the aboleth face to the one fiddling with the gems. My players are currently level 4 and I'd like to make this trap dangerous. A DC 12 Dex save avoids half of the damage or the effects of bolt 6 and 7. The ray could be any of the following (roll 1d8):
1. Red bolt, 2d10 fire damage
2. Orange bolt, 2d10 acid damage
3. Yellow bolt, 2d10 lightning damage
4. Green bolt 2d10 poison damage
5. Blue bolt, 2d10 cold damage
6. Indigo bolt, on a failed save the creature is restrained and must make a con save at the end of each of it's turns. Three succesfully saves end the spell, but three failed saves petrify the creature.
7. Violet bolt, on a failed save the creature is blinded. It has to make a wis save at the start of it's next turn. On a failed save, the creature is transported to the room beyond the door where he will have to face other challenges until the rest of the group figures out how to open the door.
8. The target is struck by two bolts. Roll twice more, rerolling any 8.

This is in fact a toned down version of prismatic ray, and that might give the players a clue on how to open the door if they don't figure it out and put gems in an incorrect order. The correct order should be in the order I have written above. The first letter of every name spells ROYGBIV (the colors of the rainbow). Having gems of a certain color that don't correspond with the colors of the rainbow might throw them off a bit.

The players might try and fiddle with the bottom eye after a bolt may have been fired at them, making sure that it won't happen again, so they can try random orders of placing gems. When a player tampers with the eyes, the middle eye is actually porous (a hard or very hard check will reveal that) and spray aboleth mucus on top of that player. A succesful DC 12 Con save will negate the mucus, but a failed check will let the character only breathe water for 1d4 hours.
When investigating the eyes in general a moderate investigation check (DC 15) will reveal the top eye is a crystal ball, placed in front of a black background. What the players don't know (or might figure out) that this crystal ball is a sensor for the aboleth so he can spy upon travelers who stumble upon his door. A succesful appraisal of the crystal ball (DC 15 intelligence check?) tells the player it's worth at least 1000 gp. If the player tries to remove the crystal ball, the aboleth will notice and will try to enslave that character through his crystal ball (rulewise it might not be possible, but I am the DM, so meh. It will make for interesting roleplay if the character fails the save). The character who tries to remove the crystal ball will have to roll against a DC 12 Wis save or be charmed by the aboleth. The consequences I will leave up to you if you decide to make use of this encounter.

When the players figure out the right order and place the gems in the recesses the right way, the door will open. The guardian will congratulate them and let them through (if he's still alive).
If the players take too long and the guardian is still alive, he will zap one of them with one of his ray spells (make it hit automatically without rolling). The ray is a confusion ray, and will give the player some insight on how to opening the door. (The confusion might be something you need to think outside the box). If that hint is enough to make the players find the answer relatively quickly, they might persuade or deceive the guardian to make him stand his ground (a difficult check, DC 15 or 20), because he or she finally remembers the correct order.

I hope it's not too long of a read and I hope you have enjoyed it. I'm looking forward to see some constructive criticism that might help me fine-tune this encounter.

Kind regards,

Zoltro