Feat[]
In the Godzilla: The Series episode "New Family, Part 2," Zilla Jr. fights his first kaiju, Crustaceous Rex. At the end of the fight, the unstable cliff collapses and causes Jr. to fall a good distance to the ground below. Then, a huge chunk of the cliff breaks off and falls on top of him.
https://youtu.be/RWR9_vsda7A?t=500
Zilla Jr. emerges from the rubble unscathed despite falling from such a great height and having a large chunk of a mountain fall on top of him. I'm going to measure the mass of rock that fell on him.
Dimensions of the Cliffside[]
According to an official style guide for the animated series, Zilla Jr. is 60 m tall at the shoulder in his horizontal theropod stance. In my screenshot, the distance from Zilla Jr.'s foot to his shoulder is 119.6 pixels. I realize he isn't standing horizontally in this shot, but 60 m will serve as a low-end for his height up to his shoulder here.
So, 119.6 px = 60 m.
On the right, I measured the height of the chunk of rock to be 235.9 px = 118.34 m and the width to be 139 px = 69.73 m.
In this shot, we can see that the cliff's length is greater than C-Rex's width from one leg to the other with his legs fully sprawled out. According to the style guide from before, C-Rex is also about 60 m in height.
In this shot, C-Rex is about 388 px = 60 m tall. His width from one leg to the other in a less horizontal position is 611 px = 94.48 m. I'll use 94.48 m as a low-end for the length of the chunk of rock that fell on Zilla Jr.
Apparently, the previous screenshot is too small to see the pixel scaling when I link to it. I decided to re-scale using a different screenshot and got slightly different numbers.
In this new screenshot, I measured C-Rex's height to be 388 px again, but this time his width is 622 px = 96.19 m. This shouldn't alter the results significantly.
Volume and Mass of Rock[]
Volume of Rock
Approximating the chunk of rock as a square pyramid, its volume will be (length * width * height) / 3.
V = (l * w * h) / 3 = (96.19 m * 69.73 m * 118.34 m) / 3 = 265,000 m^3
Mass of Rock
I'll assume the density of granite for the density of the rock because that's what first came up in a Google search and because granite can look gray. I think granite is what's commonly used in calculations.
Density = 2.65 g/cm^3 = 2,650,000 g/m^3 = 2,650 kg/m^3
2,650 kg/m^3 * 265,000 m^3 = 702,250,000 kg = 702,250 metric tons
Zilla Jr. made it out of this unscathed.
By comparison, the building that fell on Godzilla in 2014's Godzilla is said to be 300,000 tons, and Heisei Godzilla was downed for almost 90 seconds by a similar building.
This also applies to his lifting strength because he throws all of the rubble off of himself like it's nothing.
By comparison (again), the best canonical lifting strength feat I could find for the cinematic Godzilla is him lifting and throwing the 150,000-metric-ton Heisei MechaGodzilla in Godzilla vs. MechaGodzilla 2 (a manga Godzilla also once lifted the 200,000-metric-ton Biollante in a manga called Godzilla, King of the Monsters!, but even this pales in comparison).
UPDATE 6/17/16: More Accurate Scaling[]
The scaling I used for Zilla Jr. above was too crude, so I updated it to get a more accurate result. The rock scaling is unchanged.
I scaled his torso and leg separately this time. In total, his head + torso + leg regions are 131.102 px long.
In the size chart from the official Godzilla: The Series style guide, 132 px = 200 ft = 60.96 m.
Zilla Jr.'s head + torso region down to where I measured in the cliff screenshot is 115 px = 53.109 m.
His leg is 107.39 px = 49.59 m.
Together, they give a total length of 102.599 m.
So, in the cliff screenshot, 131.102 px = 102.599 m.
New Dimensions of Rock[]
Height = 235.9 px = 184.61 m
Width = 139 px = 108.78 m
Length = 96.19 m
Volume: (l * w * h) / 3 = (96.19 m * 108.78 m * 184.61 m) / 3 = 643,891.8777 m^3
Mass: 643,891.8777 m^3 * 2,650 kg/m^3 = 1,706,313,476 kg = 1,706,313.476 metric tons
Zilla Jr. not only withstood but threw 1.7 million metric tons of rock off of himself like it was nothing!
This gives Class G lifting strength.
UPDATE 6/19/16[]
After it was pointed out to me that I should take into account the part of the cliff that was hollowed out from Zilla Jr. digging through it, I realized the cliff is much wider than I assumed. The following link gives a new calculation:
http://vsbattles.wikia.com/wiki/User_blog:ZillaJrKaijuKing/Zilla_Jr._Tanks_and_Lifts_a_Cliff_RECALC
This should still warrant an upgrade to Class G lifting strength either way.