Who is Algernon and how does charlie feel about him?

In "Flowers for Algernon" by Daniel Keyes, Algernon is a laboratory mouse who undergoes the same intelligence-enhancing experiment as the protagonist, Charlie Gordon. At first, Charlie views Algernon as a competitor and is determined to prove that he can surpass the mouse's achievements. Over time, Charlie becomes attached to Algernon and forms a bond with him, eventually feeling a sense of empathy and connection as they both experience similar struggles.