Armored Core 6's biggest boss is so huge, it'd be its own landmark on Elden Ring's world map
That's one big worm.
Armored Core 6's late game Ice Worm boss is a big guy, absolutely dwarfing the player in a way not dissimilar to old FromSoft bosses like Sekrio's Great Worm or Dark Souls' sad sack lava guy punching bag, Ceaseless Discharge. As prolific FromSoft dataminer Zullie the Witch demonstrates though, the Ice Worm puts all those other bosses to shame in terms of sheer size.
As Zullie's previously shown, Elden Ring and Armored Core 6 not only share the same engine, but scale for their models as well. It's not like the buildings and cars in AC6 are just really tiny and the mechs are the size of normal guys—if you drop an Armored Core into Elden Ring, it'll really be 10 meters tall compared to everything else. So when you go one step further and bring Armored Core 6's biggest guy into a much smaller game, the results are a bit staggering.
Laid in a straight line, the Ice Worm would stretch all the way from the First Step site of grace to Castle Morne on the Weeping Peninsula (fun fact: actually an island) a whole zone away. You could ride Torrent on this thing like a highway, and one of our sweet little baby Tarnished is barely the size of the Ice Worm's spiked teeth it uses to burrow through the ground.
My takeaway? If Augmented Human C4-621, Callsign: Raven had been around during The Shattering, it would have gone down a little different. Most of these stinky demigod guys barely come up to your average AC's shin, and Raven's killed something the size of their most formidable cities.
It would be like pitting Goku against a daycare. "My name is Malenia, Blade of Miquella?" Well these are two VP-66L Laser Shotguns, each longer than you are tall. You could sort out notorious perv Mohg, The Lord of Blood with a single volley of the Songbirds shoulder mortar to the face, and unfathomably old eldritch horror, The Elden Beast, simply wouldn't know what to do when confronted with a PB-033M Pile Bunker.