Feisty Geist is episode 5b of Season 4 of Rocko's Modern Life.
After a visit to a spirit reader, Heffer is plagued by a spirit of his own.
At the Madame Doreeno store, Rocko and Heffer glaze into the crystal ball in deference to Madame Doreeno herself. Doreeno introduces the friends to the spirit life to introduce Heffer to his past life. She calls for Mortimer Khan, the forgotten son of Genghis Khan who appears in the crystal ball. He has Heffer close his eyes and tells him that his ancestor was a hungry passenger on the blimp. His weight ends up causing the blimp to crash down. Prior to this, he lived in Italy and ended up tilting a tower he was standing on. Mortimer also tells Heffer that in Mongolia, his ancestor fell prey to bribes for food and ruined his plans of conquest, literally leaving him and Mortimer to rake mud as "muckrakers". Mortimer promises revenge on Heffer's ancestor for his stupidity.
Mortimer then tells Heffer of his fate because of his family, as the latter apologizes but Mortimer is not soothed and breaks out of the crystal ball. Rocko and Heffer return to Rocko's house, Mortimer is seen hiding right inside Spunky. Mortimer, inside Spunky's body tries to attack Heffer and Rocko notices that Mortimer has taken over Spunky's body. So he ties him to a post outside and while Rocko and Heffer are trying to come up with a way to get MKortimer out of Spunky's body, Filburt come around and tells the two that he has a tube of spirit away and typo-session cream in his scooter to get Mortimer out of Spunky's body. As Filburt rubs the cream on Spunky's body, Mortimer is ejected and flies into Filburt's body.
Realizing that Mortimer will just find his way into another object, Rocko orders a jumbo size bottle of spirit away and he and Heffer sneak back into the kitchen with giant squirt guns, only to find that Filburt is missing. They finally find Filburt in the bathroom and the turtle gets another giant squirt gun to join the other two on completing the task. To Rocko and Heffer's surprise, Mortimer has taking over a toilet and emerges out after Rocko sprays it with the spirit away. Filburt returns with a squirt gun and Mortimer has taken over toilet paper, wrapping up Heffer in the process. Rocko and Filburt spray Heffer and Mortimer emerges out. Rocko and Filburt chase the spirit to the kitchen and find that he has taken over the refrigerator. Heffer comes around and sprays the refrigerator, prompting Mortimer to emerge out and locate upstairs. Rocko, Heffer and Filburt find that Mortimer is taken over every type of object in the bedroom and spray at everything around the room.
As the room is now covered in spirit away, Rocko finally spots Mortimer in the snow globe and he and Heffer return it to Madame Doreeno's store.. To thank them, Madame Doreeno gives Rocko and Heffer a free look into their past and another spirit, that of General Custer, appears into the crystal ball. When he recognizes Heffer, he shouts out threats to him and Rocko and Heffer run out of the store, with the spirit, still inside the crystal ball, shouting out threats from behind while bouncing outside.
Heffer: NO! Not the fridge!
Mortimer Khan: Spartan dog! MWA-HA-HA-HA-HA-HA!
Heffer: YOU HAVE NO RESPECT FOR FOOD! TAKE THAAAAAAAAAAAAAT!!