Nasaar waits for Caster to investigate, but is ready to simply cut it down once that is done.

(It really is a weird mushroom. One that I didn't even need to make, this one is actually a real monster in 5e.)

No matter how they approached the mushroom, once Kastor was close enough, it begins to scream again. And this one reminds him of no other fungi or plant even similar to it. Especially the screaming part of it. It's stalk planted firmly into the ground and not into carcasses like the others. Although it was Kastor's size, the screaming was not human nor beast. It is not clear how it is screaming but it is.

Kastor turns towards the others and, with a shrug, casts Shillelagh and takes a hack at it with his staff.

Attack: 24 Damage: 5 

Nasaar waits to see what happens, taking out his warhammer as well.

With a single strike, Kastor knocks the mushroom down. Although down, the screaming continues, albeit smothered now. But it does smother it enough for another noise to pass through, a sort of rhythmic breathing coming from above. At first it's hard to notice as it blends with the dark colors of the cave and the fungi, but its singular eye is hard to miss as it focuses on Kastor. It's a spherical being and seems to have tendrils, reaching out for Kastor as it slowly descends down to him.

(Initiative then?)

(You guys can act first.)

Nasaar sends a bolt of blue power into the thing...

ray of frost

Attack: 24 Damage: 4

Nasaar's ray pierces the creature. And the creature ruptures and explodes, spreading about spores of itself. It covers Kastor with it.

Kastor make a CON Save, DC 18, on fail take 11 poison damage.

DC18 CON save: 14

Kastor coughs and splutters for a moment, before saying a slightly sceptical "Thanks" to Nasaar. 

"Hmm..." Nasaar says with a frown.  "Didn't expect it to explode like that. Sorry about that."

Hari squints at the place where the mushroom exploded. "Interesting," is all the bard says.

Axon looks to Hari, "Indeed" he wasn't sure if Hari thought it was interesting for the same reasons. 

Sylvester starts to look around for the clear Apple the group is supposed to find.

Investigation: 19

"If we have a moment, I could locate it, or at least a general direction, again?"

If the group agree, and we have an uninterrupted ten minutes, Kastor will cast Locate Plants or Animals again, to search for the Apple. 

 After a couple of minutes, the spell provides the general direction of deeper into the cave, pointing more downward than forward. The cave does go deeper but its hard to tell which way will bring you deeper into the underground. 

Five passages are at an intersection, one being where you all came from

1. The mushrooms have thinned down at the passage entry and scarce pockets of them can be seen further in.
2. You can hear the sound of water from the passage
3. The bigger mushrooms populate the large passageway.
4. The smaller, more regular size mushrooms dominate the passage, but you can see most of them atop more carcasses than the entrance of the cave.

"I like the water tunnel or the tunnel with less mushrooms."  Nasaar suggests.  "Should I send my familiar down one of them to scout the way and see if there is a passage that leads lower?"

Sylvester: “I also like the tunnel with the water. Sending your familiar is a great idea. I have a sneaking suspicion that we might have to travel down the tunnel with the biggest mushrooms.”

"I agree, sending a familiar is a great idea."

((I'm going to be away for the next week or so. I'll try to get on and post when I can, but it's more likely that I'll just be able to keep up with reading and not actually have time to think about making posts, so feel free to put Kastor on autopilot, or others pilot him.)) 

(You want to send the familiar down the water path?)