Bob-omb Fortress

Bob-omb Fortress is an anomalous level found in some personalized copies of Super Mario 64, being a bizarre mix between Bob-omb Battlefield and Whomp's Fortress. The level itself is believed to be an accidental byproduct of Dynamic Level Arrangement and/or Major Level Expansion and other anomalies causing this fusion between levels. The actual contents of the level itself are relatively inconsistent besides for what is already stated, as some say it's just a reskin of one of the 2 levels using the other's texture or an actual mash-up of the geometry.

Description
The description of Bob-omb Fortress fluctuates between reports. One of the most common descriptions is Bob-omb Battlefield with the mountain replaced with the fortress or reskinned to look like a fortress, with the tower object being added on top, though others claim that it's Whomp's Fortress with Bob-omb Battlefield textures, or the 2 levels are somehow incorporated into each other, such as Whomp's Fortress being next to a segment of land from Bob-omb Battlefield. Bob-omb Fortress can reportedly even have unused assets from the levels, such as unused textures or the river from Bob-omb Battlefield. The level obviously has the same enemies as the 2 levels it came from, though other random enemies have been reported, such as Lakitus, potentially meaning they were in earlier versions of one of the 2 levels or the A.I. just added them randomly.

Missions
As you would expect, the missions in Bob-omb Fortress are usually a combination of the missions in the 2 respective levels, with changes where necessary to fit the design. Notable Star Relocation missions for the 2 levels have also been reported to be present, though whether or not by coincidence or as part of the fusion re-incorporating unused assets of the levels is unknown. Notably, there is reportedly a unique mission where Big Bob-omb and King Whomp "team up" to fight the player together.

Anomalous Levels
A rather odd and noteworthy aspect of reports of Bob-omb Fortress is that assets from anomalous versions of the 2 levels and areas associated with them, such as Flying Fortress or the Chomp Caverns, have reportedly appeared to some capacity in Bob-omb Fortress, making the level much more interesting. Whether or not this is caused by these areas being legitimately unused and added alongside other unused assets or something else is unknown.