Calamitous Offspring

Calamitous Offspring costs {1} more to cast
for each red or green nontoken creature you
control.
Destroy all creatures, then create two X/X red
and green dinosaur creature tokens with trample,
where X is half the number of creatures
destroyed this way.
"On the verge of collapse and yet, a threat that nearly resembles the ferocity of the first extinction appears..."