Stingrays

They show no hostility towards humans and attack only when provoked.

An excerpt from the article 23 facts about stingrays
Most attacks are caused by humans accidentally stepping on them and are not lethal. There have been around 17 confirmed human deaths as a result of contact with stingrays. One of the most memorable was of Steve Irwin in 2006. An Australian wildlife expert was pierced in the chest by a short-tail stingray while filming a documentary.