Oasis type creature it was added in the adventure pack that released parallel to scorched earth. It is capable of reviving lost tames.

These Gentle giants are passive and will flee if attacked.

So it's a Megachelon who flew

Quetzal, but Megachelon

~ CPG (completely guessing off the description)

Run because it might kill bob if he is standing to close to and attacks it he will die in two shots or 1.