So what are the Draining Mercury Vines? The item as the name suggests, were silver coloured vines that dug themselves deep inside the ground when sown. It was as big as one's palm and repeatedly changed shapes because of its volatility.
The draining mercury vines hide and multiply themselves inside the ground and only surfaces to drain their prey of all their energy.
When the vines surface from the ground, they are much bigger and can easily restrain a full grown adult. Another thing about the draining mercury vines was that they are not any ordinary inanimate item, but an item with intelligence.
It behaved so much like an actual living being that it could easily be mistaken for a plant monster when in fact it was just an item.