(OOC: Is all the treasure they saw also part of the illusion?)

Val describes it all to Evy, adding a word to the end of his description with a tinge of disdain: "Illusions."

He is curious to hear what his cousin sees at the end of the tunnel if not the door his magic senses have revealed. He is also hoping, though silently, that Evy can make some sense of this new information.

Does Evy see anything different than Val describes?

All of the magic is ahead. You don't sense anything in the room with the treasure or behind you. Well, except for Evy's dagger.

Evy sees everything Val sees.

“I see what you’re describing,” Evy says, confused. “But this looks important,” she points ahead, indicating Val should get closer.

Val thinks a bit more: "Right. I don't can't necessarily see through the illusion. I guess I am just aware things are a bit off around here. This important-looking part of the cave might not be so well adorned in reality."

(OOC: Am I understanding this right?)

"What is reality?" Evy asks, laughing quietly. "Everything reacts when you poke it," and she pokes Val. "Honestly, cousin, all this tension is making me squirrelly. We should get on before I do something truly rash."

A grumpy Val reacts to being poked and moves toward the door. He tries to open it.

The pair walk down the hallway to the large door. It's pretty big — about eight feet wide and probably 10 feet tall. Val puts his hand on the handle and pulls, and the door swings easily on its hinges without the slightest sound. Looking through the opening, he sees a 10-foot-wide hallway heading left and right. The walls are carved stone and lit as if by candlelight. His magic sense tells him he is within and surrounded by magic.

"A door hardly seems like something a monster would be negotiating," Evy says suspiciously. "Is this the illusion you sensed?"

"I'm almost sure it is a grandiose illusion, all around us." Val thinks for a bit... "Perhaps the Thessalhydra wants visitors to believe it is as wealthy as a dragon?"

Val tries to touch the walls or light sources or an area that feels magical to him. He is trying to confirm they are illusions by seeing through them.

-> Investigation: 6

Seeing Val investigate, Evy will also try to see through any illusion…

Investigation or straight Int roll are both +1, so: 16

It all feels just as it appears.

"Left?" Evy suggests. "Left."

Val in in front, but Evy is the driver. Left, he goes.

20 1 11 3 17 6 12 3 14 7

Val steps through the large doorway, and despite turning left as Evy directed, he quickly looks to the right to see what would have awaited them. He sees the hallway is about 20 feet long, and it turns to the left and disappears. Looking the direction he has turned, he is greeted by a very long, straight hallway. He can see the end, but can't tell at the beginning whether it is a dead end. He walks the long hallway and decides about halfway that he can see it turns to the left at the end. He continues walking, his muscles beginning to tense unknowingly as anticipation builds. The hallway is eerily quiet. Even the sound of the cousins' footsteps seem muffled somehow.

Val reaches the left-hand turn and looks around the corner. The hallway is a U-turn into a hallway running parallel to the long hallway they just traveled. He can see that after about 30 feet, there are hallways heading left and right, and after another 10 feet, two more hallways left and right. Beyond the intersecting hallways, the hallway straight ahead is another extremely long hallway, and he can't make out the end or if there are more hallways left and right after the four he can see.

Evy approaches Val and peeks her head around the corner... so, the next hallway runs parallel to the one they are in, and has intersections that would pass through the hallway they are in, but don't appear to from this hallway? In other words, it makes no logical sense?

Val had the same question as his cousin. He theorizes: "Perhaps parallel but at slightly different elevations?"

Regardless, he moves closer to the first pair of perpendicular passageways and peeks left, then right.

Evy, you are correct. Val, no elevation change. It makes no logical sense.

5 6 4 4

Val, you walk to the first intersection and look both left and right. Both directions, the hallway is about 20 feet long and then turns left.

"Val, come back," Evy calls from where she is still at the first U turn. "I'm worried this is some sort of illusory maze." She glances back the way they have come, to make sure the original hallway hasn't changed any.

OOC > old D&D used to have a mechanic where you could try to "disbelieve" an illusion. Does 5e have that?

"I think you are right," Val says while walking back to his cousin. "This may be why the troglodytes were snickering."