In suburban Connecticut, upper-class high schooler Amanda (Olivia Cooke) euthanizes her crippled horse with a knife, resulting in charges of animal cruelty.

Based on this passage, what did amanda do to the horse in thoroughbreds? Let's think fast. Stream of consciousness:
To answer the question, consider the following: In suburban Connecticut, upper-class high schooler Amanda (Olivia Cooke) euthanizes her crippled horse with a knife, resulting in charges of animal cruelty. So the final answer is euthanizes her crippled horse with a knife.