Before Pokemon really took off, there were a lot of designs that didn't make it off the cutting room floor. Famed illustrator Ken Sugimori came up with many of those characters, even helping form Game Freak itself many years back. These unearthed designs are particularly comforting.
As Pokemon historian Dr. Lava reminds us, Godzillante was one of the first creatures crafted before Pokemon was a thing, but for pure design purposes. Godzillante was basically a draft of how the game would work, as the doodle contained HP and TP bars showcasing the battle system. Similarly, "Gorillaimo," possibly a take on Donkey Kong or King Kong, was created for the same purpose. This was all revealed in a previously released Game Freak tome detailing the creation of the then-called Capsule Monstersproject, but was worth bringing up in case you haven't seen it! Artist the-fake-dexter provided re-imaginings of those doodles to really bring them to life that you can peruse below.
As many have pointed out, Godzillante may have slowly morphed into the "substitute" doll, or taken the form of the various Pokemon statues littered about the game world. Either way, he will be missed and I'd love to see him as a proper 'Dex entry someday.