I've had 2 dryers catch on fire while drying clothes. On one, the thermostat that tells the dryer how hot to get went out. The dryer and laundry area went up in flames. The second, the outlet was struck by lightening while the dryer was running. Fried all the circuits on that wall, and of course, the dryer.
One time I had a huge, huge rat come in through the dryer vent. That was a frightening surprise.
No one was hurt in either of the fires. I faithfully clean the lint trap.