Alyssa would have called back Hue for her scout, but would agree that Leon's owl would be better. "Alright." She'd step off to the side and prepare to bless the three of them.

Preparing: Bless depending on what Leon will report.

(It's a questionable move, but our beloved Crawford twitted once, that as a DM he would allow re-summoning familiar behind the wall)

Leon called forward his owl, sent him away and then moved to the doors to summon him back on the other side. The seal, that kept doors locked was gone now and floor by the doors was covered with fine sand instead, but they stayed closed. Owl appeared on the other side and the message Leon got was about big dark space, filled with unmoving figures and among them one that was still moving, touching the those standing still. That one turned it's gaze to the familiar - and the owl's thoughts were filled with the vision of two bright red eyes burning with raging hatred. 

DC 14 Constitution saving throw for owl, please.

Owl con save: 5

As information from the owl cuts off, Leon will attempt to re-summon it back to his side. Not recasting the spell, just sending to extra dimensional space and then back to his side. Might not work, depends on what the DM thinks here and what actually happened to it.

Bernard scratches his head and says, "This may be a strange idea but what do you guys think about taking a rope, trying torches at different intervals and having one of you guys pull it in and then just drop it when you first attack?  That will give us light that would persist.  The dark vision is good and l but if you get it then that could fail and two of us would be blind."

((That's a very good question I can not find answer too - what happens with the wounded familiar if you re-summon it? You can still dismiss it - Crawford said so - https://www.sageadvice.eu/2015/09/26/familiar-turned-to-stone/ but it seems it supposed to stay this way. Open to ideas and interpretations here!))

What Leon got back now was a perfect statue of owl as of made of colorful but hard glass: shiny, smooth with every feather and colorspot perfectly preserved. But the bird did it job and Leon got the vision of a big (about 80x40ft) room with the hooded creature moving among and doing something with the statues in that room.

Ramious shrugs at Bernards idea.  "Sounds fine to me. I'll be runnin right at it hoping to wrestle it down.  That will hopefully help us..."

"Perfect, so then you can let go of the rope right before ya hit.  Should give us some lighting just in case," Bernard says.  He then goes about pulling out his torches and rope and ties one off every 10 feet.  5 total? One on each end and 2 in the middle.  He then lights them all and gives one to Ramious to hold.

"Sorry pale, this will likely make you the prime target... but wrestling with him would likely do that too."

(Darkvision won't go down if Leon does, as it is not concentration. It can be dispelled though.)

Leon sighs at the owl statue. He dismisses the owl, knowing it is of no use in the statue form it has now.

"So we are dealing with something that turns creatures into glass statues." Leon says. "Any ideas what that might be?" He describes it to the others, at least what he was told about it before his owl was turned to glass.

Would this be an arcana, nature, history, or some other kind of check?

Ramious shrugs, "Everyone has a job to do."  He grins a toothy grin. 

Ooc: I typed in darkvision and dang it, it auto corrected me to darkness and I just clicked and looked for a C for concentration.  You are correct.  Still, just in case, maybe it doesn't like light ot fire or we have to burn it.  Or doe some Hercules stuff with a hydra.

Arcana/History I say, but the general idea of a creature, turning living into variation of stone with it's gaze - is universal enough to know it. There is more than one creature with such ability, of course, and there had to be a reason to deal off that one particular.

Still, every legend about such creatures includes mirror - that should not be a secret.

Alyssa would nod along in thought as Bernard proposed his idea for light. "I agree. It's worth providing backup/extra light just in case. We have nothing to really lose by doing it." Her eyes would then fall over Leon and his statued owl. She'd listen to his description, pondering the possibilities of what it could be. Though a part of her wondered if they would ever be able to know for sure. These ruins are so ancient, it may even just be unique to this temple? The archaeologist would review her notes, dusting off her knowledge and experience in the field to see if it'd be of any use in this case.

History: 11 Guidance: 1

Leon arcana: 22

Leon was one to "see" the figure and the hall and can tell, that while to his knowledge the nature of the material does not truly matter - glass or stone, the magic is the same, that movements of the figure between the statues... He does remember that some magic allows to return statues to life, but there is other, that simply re-animates the stone, turning it into obedient servant of the caster. He did not see that happening, but does know about such possibility.

"Well, a medusa is in there, I have no doubt about it." Leon says with a frown. "Probably animating some of those statues to fight us... Probably shouldn't give it any more time than we already have to do so, who knows how many statues it has in there..." Glancing to the others. "We ready to do this then or what?" He moves to the doors, ready to shove them open. "And where is that mirror?" He asks Bugs. "Maybe you can look into that, without calling on its magic, to see the medusa and not get turned to glass."

"Alright, so.....we ready?  We crack open the door, I rush in with this weird rope of torches, find where this thing is wrestle it down. You guys back me up?"

Bernard, takes a quick looks at his bracelet and nods.  He the hoists up his bow with arrow ready.  "We've got your back."

"Remember, there is likely to be other things, not just the medusa." Leon cautions them. "Watch out for animated glass statues."

Ramious nods, "Right. Medusa. Sure.  Wait a second, wait a second. Are we talkin a thing with snake for hair? If I go wrestle it, won't the snakes bite me to death?  Uh....hold on a sec..."