Answer:
negative consumption externality.
Step-by-step explanation:
A negative externality arises when the production or consumption of a finished product or service has negative impact (cost) on a third party.
On the other hand, a positive externality arises when the production or consumption of a finished product or service has a significant impact or benefits to a third party that isn't directly involved in the transaction.
In this scenario, your neighbor enjoys seeing the grass in his yard grow wild and free, a practice with which you disagree because it poses a danger on the people around as snakes and other poisonous animals may breed or live there.
Hence, this is an example of a negative consumption externality because it's the potential of causing you harm or endangering your life.