Eagles Superfan Shows Off Insane Game Day Cave in New Doc, Spent My Savings!

How far will one fan go to support his Philadelphia Eagles??

How about spending his LIFE SAVINGS to come up with the most badass at-home game day setup -- complete with a full bar!!

Die-hard fan Barry "The Hatchet" Vagnoni opened the doors to his incredible Eagles shrine in Reading, PA for the upcoming doc, "Maybe Next Year" ... which follows Philly fans during the 2017 Super Bowl run.

73-year-old Vagnoni says in the doc (set to release on Nov. 10) he got his inspiration to come up with the perfect viewing experience after watching the movie, "Field of Dreams" ... essentially saying if he builds an outlandish sanctuary, Eagles fans will come.

So, that's exactly what he did -- convincing his wife to spend their savings to make an addition to their home for friends and fam on game day -- and it's WILD.

The place is decked out from floor to roof in Eagles decor and can seat a BUNCH of people.

"The passion for the Eagles came from my dad -- he loved the Philadelphia Eagles," Barry tells us. "He wasn't over the top like I am. I've grown into a coo-coo."