Challenger (born ASM Tofazzal Hossain; 1959 – 12 October 2010) was a Bangladeshi television and film actor known for his work in many dramas and movies. He became popular for his performances in television dramas and later appeared in several feature films.

Challenger was born in 1959 in Dhaka, which was then part of East Pakistan (now in Bangladesh). His birth name was ASM Tofazzal Hossain and he was also known by the personal nickname Sadek. His younger sister Monira Mithu, is a well-known television actress in Bangladesh. Hossain was nicknamed "Challenger" by writer, director Humayun Ahmed, when he debuted his acting career in the television drama Hablonger Bazare.

Challenger was respected by colleagues and audiences for his natural acting style and professionalism. In 2009, he became ill during the filming of Onath Babur Bhoy and was later diagnosed with brain cancer. He was taken to Singapore for treatment but his health did not improve. He died on 12 October 2010 in Dhaka at the age of 51. Actress Monira Mithu is Challenger's younger sister.