What an amazing find! I think it almost looks like an agatized mushroom.
Whatever it is, it's agatized. An agate doesn't have to just be an agate. There are also agatized coral which are known to be found in florida. Some type of agatized "something" geode is possible as well. The inside looks really weird!
Thank you for using the #rockhound tag! Manually curated by @bitfiend