Creating new creatures for games is easy. Just take two normal animals and cross them.

Like, say, a shark and a squid. A shark-like creature with tentacles!

Or a sea lion... crossed with an actual lion!

Or an owl crossed with an elephant. Or an... armadillo crossed with an elephant!

Or an eagle with the head of a wolf! Or a spider with the head of a wolf!

And of course, one of the greatest original Dungeons & Dragons monsters of all time, the owlbear.

You think we're kidding??

(And just in case you thought owlbears couldn't actually be cool, here's an art competition to reimagine the owlbear concept, and the entries. EDIT: The linked pages have vanished from the net, and I can't find them anywhere. So instead, try some of the cool art you can find using Google image search.)

Transcript

[SFX]: Whoooooooosh! {Obi-Wan's ship takes off by itself}
Obi-Wan: {watching it leave} Okay, I need some transport.
Yoda: Use a riding lizard!
GM: A what?
Yoda: They live in the sinkholes and their claws let them climb up and down. And they have feathers!
Obi-Wan: Feathers?
Yoda: Yeah, they're like the dinosaurs in my novel!
Obi-Wan: Okay. I ride the...
GM: Riding lizard.
Yoda: Yay! They're called varactyls!
Obi-Wan: I look for General Grievous. I let the Force guide me. Carefully, so I don't spring any deadly traps.
Yoda: Her name is Boga!
GM: Okay then. After <roll>... four hours of searching you approach what looks like... a meeting.
Obi-Wan: A meeting, whoa, look out.
R2-D2: Hey, some of my work meetings are pretty deadly.