A friend of mine had an iguana that would eat weed. We'd smoke up and feed this thing juicy little buds and it would vege out with us.
One day it fell asleep on the water heater. We figured it just liked the warmth. After a few days we started to suspect that something was wrong so he went over to check on it. The thing was bone dry and as stiff and brittle as a twig.
We actually managed to break a lizard.