Beyond the Steam Tunnels

1. You should have brought the reanimated hand along with you into the lair.
2. Well, it's not bobbing for apples.
3. REACH INTO THE POOL.
4. There's a power line there. Maybe you can electrocute the mass.
5. Chop the power line with the axe to expose the live wires.
6. You can't approach the mass close enough to electrocute it without it snatching you, so you'll have to electrocute it indirectly.
7. Notice the cables and tentacles entering the box.
8. OPEN THE BOX.
9. You can disconnect the coaxial cable from the socket.
10. PUT THE POWER LINE INTO THE SOCKET. This will fry the mass (assuming you haven't saved it by cutting its cablelike appendage).