Which adjective best describes something or someone that is full of malice?

The adjective "virulent" is the most appropriate choice to describe something or someone that is full of malice because it conveys a sense of extreme hostility or bitterness. The term often implies a harmful or destructive nature, particularly in contexts related to behavior, attitudes, or feelings that are meant to cause harm to others. It captures the essence of malicious intent, suggesting that the subject is not only negative but also dangerously so, similar to how a virulent pathogen can cause severe illness. This aligns perfectly with the idea of malice, which involves a desire to harm or hurt others.