Villain(s)  Mad scientist, zombie

Actor(s):  John Ashley, Angelique Pettyjohn, Eddie Garcia, Ronald Remy

Brief Description  The Mad Doctor of Blood Island (1969) is a cult-classic Filipino horror-exploitation film co-directed by legendary exploitation filmmakers Eddie Romero and Gerardo de Leon. Produced by Hemisphere Pictures, it serves as the second official entry—and third overall—in the famous "Blood Island" cinematic universe, preceded by Terror Is a Man (1959) and Brides of Blood (1968).

Plot:
The film opens aboard a boat chugged toward the remote, tropical "Blood Island". Three distinct travelers are on board, each with a different motive: Dr. Bill Foster (John Ashley): A young pathologist sent by medical authorities to investigate disturbing reports of local native corpses found drained of blood or contaminated with green blood. Sheila Willard (Angelique Pettyjohn): A young woman looking to find and check up on her estranged father, an émigré who stopped responding to her letters. Carlos Lopez (Ronaldo Valdez): A worried native of Blood Island returning from the mainland to rescue his widowed mother, Doña Anna, from the island's increasingly dangerous atmosphere.

Upon arrival, the trio discovers that the island is under the tight, de facto control of the brilliant but sinister Dr. Lorca (Ronald Remy). The travelers quickly find their personal lives upended: Sheila discovers her father (Tony Edmunds) has deteriorated into a hopeless, vegetative alcoholic. Carlos is horrified to find that his mother, Doña Anna, has become Dr. Lorca’s live-in mistress. Meanwhile, a series of gruesome, limb-tearing murders plague the local tribal village. The locals blame a legendary, sub-human green beast stalking the jungle. Dr. Foster's investigation eventually intersects with Carlos’s personal quest. Carlos discovers that the tomb of his late father, Don Ramon, is entirely empty.

Confronted with the truth, Dr. Lorca proudly confesses his horrific experiment: he had injected the dying Don Ramon with an experimental chlorophyll-based drug extract. Lorca believed that blending human biology with plant matter was the secret to genetic mutation, ultimate healing, and eternal youth. Instead, the drug mutated Don Ramon into a mindless, green-skinned, mud-caked monster with chlorophyll running through his veins. The monster escapes its constraints entirely, going on a brutal rampage across the island, dismembering locals and attacking naked women in the jungle. Driven by a residual memory of his past life, the mutated Don Ramon returns to Lorca's manor and kills his former wife, Doña Anna.

Dr. Lorca captures Bill and Carlos to protect his life's work, but the monster breaks into the laboratory. Don Ramon brutally kills Dr. Lorca, smashing the equipment and setting the entire laboratory ablaze. As the facility burns to the ground, Bill, Carlos, Sheila, and her newly sober father escape the fiery inferno. They board the boat and sail away from Blood Island, believing the chlorophyll monster perished in the flames. However, in classic exploitation-horror fashion, the final frames tease that the nightmare may not be over, paving the way for the sequel, Beast of Blood (1970).