Blue's monster looks like a creepy, ass tree. Essentially it's going to be all about making more creepy trees like itself. When it finds a victim, it's branches will try to surround them and grow to engulf the person entirely and plant them as another tree statue. It'll be very determined to grab and people and drag them back close to it to keep them there as it assimilates them. And once caught, it can be hella hard to get out of. It doesn't feel pleasant, as it doesn't kill you. Instead it just imprisons you inside it, and the longer you're in it the more your body merges with the bark. It's cold and empty and makes a person a prison in their own selves. Once imprisoned, the creature will plant the roots in the ground and leave the victim to slow assimilation in the new tree statue. Blue will be terrified of this, and doing her best to actively avoid going anywhere near monsters. So she'll try to stay at Hope's temple with Gansey, but being the hard-head she is she will go out and try to get supplies to bring back. I'd really like her to get swallowed up by this thing once and have to be pried out of the tree if anyone's willing!