Modern Primitives (The Grim Adventures of Billy & Mandy)

"Modern Primitives" is the first half of the fourth episode in the fifth season of The Grim Adventures of Billy & Mandy.

Plot
When Billy digs his front yard he finds a frozen caveman, who is actually Fred Flintstone (from The Flintstones; and voiced by James Arnold Taylor), but whom Billy names Jake Steele. Billy tries to acclimate Fred to the modern life but the job is not easy. When Fred is taken to school, he predictably goes out of control, kidnapping Miss Butterbean and running away in Principal Goodvibes' car.

Why It Rocks

 * 1) The plot is very interesting and original, with Billy finding a frozen caveman in his front yard, Grim unfreezing it with his scythe and Billy introducing him to the modern life of a human.
 * 2) * Speaking of which, the caveman Billy finds in his front yard is actually Fred Flintstone - from Hanna-Barbera's most iconic show, "The Flintstones". He even says his signature "Yabba Dabba Doo!" catchphrase and has the correct outfit design.
 * 3) The Hanna-Barbera sound effects played when Fred runs around is pretty funny and a clever reference to the classic cartoons.
 * 4) Some funny moments, such as Harold crashing his car near the house and Fred running around the place as mentioned above.
 * 5) Billy at least tries to do a decent job on introducing Fred and giving him a taste of the modern life.
 * 6) The way Billy, Mandy, Grim and Irwin chase the caveman is pretty clever and Billy makes a reference to the 1982 movie, "E.T. the Extra Terrestrial" by saying "this is like that movie with the extra terrestrials who wanted to make friends with those kids" when going airborne.
 * 7) The caveman kidnapping Miss Butterbean by smashing the window and crashing Principal Goodvibes' car can be justified due to him not understanding anything at all.
 * 8) Emotional/Funny Ending: Fred gets frozen in ice cream when destroying the ice cream truck, Billy thinks he's dead and buries him under the grass and then says goodbye. But then, we cut to ancient Egypt and the caveman is unfrozen again along with Billy and the monster eats Fred's brain - but then again, he's a caveman.

Bad Qualities

 * 1) Some gross-out humor here and there, such as that one close-up Harold made when talking to Billy about keeping the caveman, Billy shaving Fred's back to reveal his skeleton, Harold and Billy eating with their mouths open and a monster eating Fred's brain at the end.
 * 2) Although justified, the caveman was unlikable for going on a crazy, mad rampage by throwing Miss Butterbean out the window and smashing it, Principal Goodvibes' car and even the ice cream truck.