Joan the Mouse, Punisher, Spacker Dave (former neighbors); possibly Spider-Man
Mr. Bumpo is morbidly obese and can barely walk down the street, provided he's even able to make it out of his apartment. His primary assets are a virtually unlimited ability to consume mass quantities of food, and the fact that he's heavy enough that no normal human can lift him unaided.
Nathaniel Bumpo loved fast food. His days were never-ending journeys from pizza to french fries to burritos and back again--all consumed in vast quantities. Due to this, Nathaniel became morbidly obese--weighing in at 1,200 lbs. Mr. Bumpo usually stayed in his apartment in lower Manhattan, living off disability checks, his envelope-stuffing business, and his neighborhood's wide variety of fast-food home delivery services. However, Nathaniel shared his joy whenever possible. Bumpo was very friendly to his fellow residents and would often say hello and even engage in friendly conversations with them.
One day, Mr. Bumpo received some coupons for the All-You-Can-Eat lasagna at Vito's Pasta Trough. Nathaniel decided that he wanted to test the boundaries of this "All-You-Can-Eat" buffet. While eating his food at the restaurant, Spider-Man came crashing through the window--having fallen victim to a devastating blast from Electro. After asking Bumpo to play along, Spider-Man took Bumpo's plate of lasagna and dumped it on his chest to form a mound of food that even close-up looked like a horrific wound of ripped flesh. Spider-Man topped of the illusion by taking a shard of glass off the table and impaled the food to make it look like it had pierced his heart. Fortunately, Electro fell for the trick, and flew away screaming his success at being the man who finally killed Spider-Man. After a few minutes of rest, Spider-Man got up and thanked Mr. Bumpo for his help. Spider-Man then took off after the criminal again. Surprised from the whole situation, Mr. Bumpo sat there for a few moments--thinking about how interesting the experience had been. He also thought of how hungry he was now. (To learn about Spider-Man and/or Electro, click on the highlighted names above.)
Later, a Mr. Smith moved into the same apartment complex as Mr. Bumpo. (At the time, he did realize that "Mr. Smith" was actually the Punisher (Frank Castle). One day, "Mr. Smith" even helped dislodge Bumpo from his own doorway. (Click on the highlighted name above to learn about the Punisher.)
On one occasion, Mr. Bumpo had a minor stroke and called 911. The paramedics couldn't physically get him out the door, so they had to smash a hole in the wall to get him out. Mr. Bumpo retunred home soon afterward with orders to get more exercise. So, Bumpo decided to walk down to Sal's and pick up five pizzas inside of ordering in. Soon after returning home, Nathaniel was enjoying his pizzas when the Punisher came crashing into his apartment--thrown there by the Russian. When the Punisher realized that the pizzas Mr. Bumpo had were fresh and steaming hot, he hurled one of the pizzas into the Russian's face, scalding him, and then he tripped him. The Punisher then used Mr. Bumpo as weapon by pushing Bumpo on top of the Russian. Mr. Bumpo's massive bulk smothered the Russian, who was unable to move due to the mass weight of the man (the Punisher was on top of him to steady him). (To learn about the Russian, click on the highlighted name above.)
Soon after, the Punisher moved out of the apartment complex. However, he left behind a large stack of bills (Gnucci's mob money) for Bumpo and his neighbors, Spacker Dave and Joan the Mouse. A brief note told them to leave the apartments to avoid anyone else who would come looking for the him.
More recently, Mr. Bumpo's obesity caught up with him and he now spends his life in a hospital.
There is nothing there, but here is link to the bio of Mr. Bumpo on Marvel.com, http://marvel.com/universe/Mr._Bumpo.