Giant Squid? 
There's a shot of it here, in this review of Aces High 1.07:
http://www.combatsim.com/memb123/htm/2001/07/aceshi107/
Notice how the Yak's cockpit hasn't changed since then. Underrated plane, that; just seems to get ignored a lot. I'll quote from their review of 1.05, emphasis added, and bear in mind this is from 2001, the days when 56.6k modems were hot stuff:
"The triple-A tracked vehicles and the panzer can prove to be interesting diversions, as the brand new P.T. boat is. Sometimes it’s a hoot to drive out a ways and park on the outskirts of your besieged airfield and blast away at incoming attackers. The occasional Panzer attack on an enemy vehicle park or airfield can also be fun,
especially when coordinated with others. ... I spoke to HiTech Creations about these seemingly unrelated add-ons, and was told basically what I thought to be the case. These are fun extensions of the sim, for sure, and more non-aircraft vehicles will be added. I was assured, however, that Aces High is and always will be first and foremost a flight sim. I’m glad to hear it, personally. There is far too little focus these days, and “mission creep” can foul a sim beyond recognition."
This guide from 2001 has a couple of articles from someone called Skuzzy, whatever happened to him, eh?
http://users.eastlink.ca/~sconrad/articles.htmThese screenshots include a very attractive sunset, which I miss:
http://users.eastlink.ca/~sconrad/screens.htmNo, wait a sec, there was an almost identical thread back in 2010, with larger shots of the squid, which seems to be eating a ship:
http://bbs.hitechcreations.com/smf/index.php/topic,295714.0.htmlDid it actually move? I assume people have scoured the current set of maps for something similar; I've always thought it would be great if there was a black monolith hidden away, or a secret teleport, or a giant mirror or something. The above does raise the question as to whether (a) they should just drop the II and call it "Aces High" and (b) what it would take for an Aces High III (probably a huge overhaul of the graphics engine, bringing it more in line with IL2 and its heirs, hopefully without the bugs).