Hilarious in Hindsight: An actual (extinct) flightless caracara was described in 2008, making the Carakiller this.
This series speculates that 200 million years in the future, nearly all land vertebrate life, including humanity, have been rendered extinct and sealife will move to land to fill the void, with squids becoming the new dominant species, and a particular squid species being hinted to become as or more intelligent than humans and making civilization sprout on Earth again. Jump 12 years later and out comes a game whose lore has that scenario actually happen.
Ugly Cute: The Squibbons, Spinks, and Desert Hoppers.
The Poggle. Something about those big eyes and invisible mouth is enough to send chills down the viewer's spine. Doesn't detract too much from their cuteness, however.
The Woobie: Poggles. They're so cute. And so tasty for spiders. That, and they're also the very last mammal species on the planet.
The scrofa who gets trapped in the salt flats
The Rainbow Squid who gets eaten by Sharkopaths.
The Shagrat who gets killed by a Snowstalker.
They Wasted a Perfectly Good Plot: Not only is it totally implausible that any ice age short of another Snowball Earth would wipe out anywhere near all marine mammals (who have so far survived many relatively recent ice ages), but doing so for the series cuts off many fascinating possibilities to explore. For instance modern river dolphins evolved when shallow inland seas retreated and became river basins, this could happen again perhaps in new ways. It would be fascinating to see what the first freshwater baleen whale might be like! Or, what might future pinnipeds be like if they evolved to become fully aquatic? Would they resemble modern cetaceans? In what ways would they be different? Could cetaceans ever develop a civilization?