The idiom "alter ego" refers to someone who is similar to a person but different from them, often in terms of their personality or behavior. It can also refer to an alternate version of oneself that one may present to others.

The idiom "blood on hands" refers to a situation where someone is responsible for a crime or a wrongdoing that has caused harm or damage to others. It implies that the person has committed an act of violence or aggression that has left physical evidence in the form of blood stains.

The idiom "quantum leap" refers to a sudden and significant change or advancement that occurs at an unprecedented speed or level of innovation. It is often used to describe something that has the potential to revolutionize an industry, field, or society.

The idiom "crocodile tears" refers to fake or insincere tears that are shed by someone for the purpose of deceiving or manipulating others. It suggests that the person is not truly sorry or affected, but is only pretending to be in order to gain sympathy or benefit from others.

The idiom "pull leg" is a playful way to tease or joke with someone, often by pretending to take their advice or suggestion seriously, but with no intention of following through.