system
Given the following post, respond as if you're commenting on Reddit:
human
Has the evolution of mammals and of the human race been a steady progression of increasing body size, or were there periods when our ancestral lineage underwent significant decreases in body size?

Can the possibility be ruled out that we have direct ancestors which were larger than human beings? I cannot think of a particular epoch in which this could have occurred. There could perhaps have been a large synapsid in our lineage, or perhaps there was a very large fish.
gpt
There are lots of extinct megafauna larger than any living relatives: woolly mammoths, direwolves, saber-tooth cats, ground sloths, giant wombats. These aren't direct ancestors of modern species, but they are older, larger relatives.