DO NOT PANIC!!
My regular Internet is down (I'm on my phone) or I would post some photos.
If you search google images (type in crown rot daylilies) you will see what it looks like. It's a fungus/bacteria that is in the soil. You cannot see it unless its the shoestring root rot and it intertwines with the daylily roots and looks like thin shoestrings.
Yes your daylilies would more than likely be slimy if crown rot is far enough along.
I'm not sure what you have found, maybe some type of underground mushroom type thing.
DO NOT destroy your daylilies, they will most likely not infect your other daylilies even if it was crown rot.
Do you have an agricultural extension office near you where you can take this thing to and see if they know what it may be?
