Experiment Notes 1: "August 13. The Creature is ready. Parts are currently on ice, prepped for surgery. Any day now... Immensa Creatura"
Experiment Notes 2: "Vulture Wing 4-5 lbs"
Experiment Notes 3: "Bear Heart 22 oz"
Experiment Notes 4: "Boar - Sus scrofa Human - Homo Sapiens"
The Manmade Mutant is a possible reference to the monster "ManBearPig" from the animated sitcom South Park. Being cobbled together from the parts of various deceased creatures, including a human, it may also be a reference to Mary Shelley's Frankenstein.
Arthur's drawing: "And I thought I knew folks with strange hobbies."
John's drawing: "Folk can be, well, real weird."
The mansion where the strange creature can be found.