My main male breeder Leachie draws blood every time i have to pick him up.
Geckos can inflict some damage.
My redtailed boas will bite and not let go. My big female tried to swallow my hand but she couldn't get around my extended thumb. Feeding response can be a terrible thing lol.
My ball pythons are all non biters except for my male yellow belly. He just does not like me. He sometimes bullies his food before he eats it. He bites the poor rat then backs off. Like he is just mad at it. Then after a while he bites and coils. Im thinking of calling him Vader just because of all the hate.

Dogs and cats bite and they call it a social disorder and will try to put the animal down. Reptiles bite all the time and people call it natural.
Its normal for all animals to bite its their primary defence.
I had a water monitor run under my dresser and i mistakingly put my hand under it to pull him out. It took me 30 minutes to get my hand free. Felt like i was getting torn apart by a T-Rex. Good times...