We found it...

Excerpted from an Ace Laboratories Log book:

"Experiment 239-D, Log 17: The specimen escaped this morning. It is unknown what it is capable of. It is highly recommended we put significant effort into finding it immediately. It's last known location was the surrounding tundra, It is speculated to be able to grow up to 24 feet tall and has an estimated wingspan of 54 feet. Currently it has claimed 3 victims, all being low level researchers. It currently has no known weakness. Further experimentation required" -Researcher Joseph M. ██/██/1985

HT-015 was retrieved from a mission to the abandoned Ace Laboratories on ██/██/2020. It was found prowling the grounds presumably looking for food. Further experimentation on HT-015 is not recommended. All lab notes retrieved from Ace Laboratories regarding HT-015 have either been incinerated or stored in a secure vault in MES labs Location: █████.