nogray
Adventurer
Utgard-loki
Since you've used it twice, I figured I'd chime in with the well-known explanation in the myth itself that this was an illusion created by Utgard-loki, a magical giant. He placed the illusion that it was his cat (small to a giant, not to Thor -- at least according to the versions I have read) as a part of a trick against Thor.
Jormungandr encircling Midgard while simultaneously being a small cat in giant's hut is unexplainable.
Since you've used it twice, I figured I'd chime in with the well-known explanation in the myth itself that this was an illusion created by Utgard-loki, a magical giant. He placed the illusion that it was his cat (small to a giant, not to Thor -- at least according to the versions I have read) as a part of a trick against Thor.