Lava lamp? Pfff. YouTuber bfayer made a life-a-lamp. His calls his invention the Liquid Lifebar. It reflects to the amount of health or mana of his character in Terraria in real time. If he has a lot of health, the lamp’s water level is high and it glows a healthy green. But if he gets hit, the water level drops and the color gets warmer. When it turns red, he’s dead.
Bfayer made a time-lapse video of his build process. You can see the Liquid Lifebar spring to life at about 3:50 in:
Check the video’s description on YouTube to see the complete parts list. It would be awesome if bfayer could make it work in reverse as well, i.e. the Liquid Lifebar dictates the amount of his character’s health or mana.