What Kind of Creature Am I?

Started once upon the thyme
There a lot of brave and awesome stories start
Under some old oak and pines
In the time between the summer and the winter
Rolling in an open grave
We see an egg about the size.uh.of an egg?
By a monotreme was it laid?
Or maybe by a giant made of rock? Oh!

Never mind it's origin!
We hear and see the egg (of course) begin to crack
And slithers out, a creature grey
Wearing tiny face full of wonder
From a slither to a crawl
The creatures of the bush all introduce themselves
Little things like: I'm a bird! - or: I'm a fish!
Or: I'm a hungry snake! (Scream)

He met a lot of things that day
And surely went and met a few ones more
Walking now, he found a lake
And he was heard to say;

See. Me? Is that I in Lake reflection?
Sloth-hairy, bat-of-a-wing, but
Thorny & horned like a rhino?
Scale-tailed not unlike a dragon, oh!
What kind of creature am I?

Heading further in the bush
It came across a weather-beaten sign
Annual meeting of the owls
The smartest creatures in the region!
It was something of a barbeque
They were feasting there, on whiskey and sardines
When a crackle under clumsy paw
Caused them all to stop and turn around

We've never seen a thing like you!
And we've seen every creature known to owl!
Gazing through their monocles
With their heads all a-swivelly (as owls do)
Then, an information overdose
Consulting every book that they could find
Everything from Count the Frogs!
To Pigs and Hogs, to "Spot the Cephalopod!

The parliament was at a loss
Hooting puzzled, till one came forth and said
"Oh! We haven't got a clue! But we know who do"

Jewel-eyed? underbite fangers... and whiskers?
Claws, paws and toehidden™ blisters
Surinam-toad-backed, with ink sac!
Funnyboneless, and what's that?
A blow hole there on the back of its neck?

It travelled west (but too far inland), following the leaf
And charcoal map exactly as the owls had drawn
It's there - they said - the weird all-knowing dwells
With mushroom suckers
And enormous brain (proportioned to its brawn)
Diving in the waters for the first time
Was at first alarming, (calming though it was, eventually)
Following the pulsing rhythm of the triple-hearted one
Our poor protagonist was heard to speak

Failed to feel the water slowly boil, absorbing into bone
Gigantism setting in and turning muscle into stone
What kind of creature am I?