a fire. i'm so afraid of fire. really sorry for your loss. that must have been so awful. i don't have a good heat lamp set up figured out. i'm afraid it will break in the night & drop hot glass that will ignite the litter on the floor. because i can't seem to figure out a smart way - my girls & charlie have had some chilly nights. we live in Texas though & chilly to us is nothing compared to y'all further up north.