I did this quick calc of counting the number of visible feathers on Ho-Oh and multiplying it by the AP of
one feather and I got
6.50253E+15 Tons of TNT or
High 6-A results
At the same time though, I found
the calc to be rather screw-y, I tried to copy the exact method on my spreadsheet, and I instead got
7.71796513614550E+10 Tons of TNT or 6-C results, and I sure as hell have no idea as to how
@Executor_N0 got the mass of 6.42910657e14 kg without the density used
And that's not mentioning the calc creator didn't convert from km to m