Welcome to Gertrude's Potion Room. She's a friendly witch with a particular fondness for spiders and eyeballs. She spends her time cooking up potions in the cauldron in the back of the room and bottling them up ready for later use. The potion in her hand is the one she uses to bring the skeleton to life so he can help her with her potion making.
I was inspired to build this as a compact fun build for Halloween. The keen-eyed amongst you will see that Gertrude is an adaptation of the Spider Lady from Minifigure series 14. I think she fits the scene perfectly, particularly given the huge spider in the back room.