Lil Baby pulled out all the stops for his 9-year-old's birthday bash ... throwing a Ravens-themed party that felt like a real NFL game -- and it even featured a surprise from Lamar Jackson!!
The rapper's son, Jason, was treated like a king during the event ... which was decked out with a flag football contest, concessions, postgame interviews and, of course, cake.
The kiddos even got their own hyped-up entry .