Saw a shark. Not Stromwind daily rock lobster quest. It was something else but didn't fight it myself. It was huge. I didn't see it fighting under water because I didn't get under water in time
Bet it was Ol' Gummers in Redridge. There used to be a different elite lake monster out there, but apparently Gummers got knocked inland and ate it. Far as I know he isn't part of any quest or anything, just another reason to be careful around that lake.
FYI elites are more challenging than regular mobs, and they're designated by a gold dragon around their picture. You can kill one around the same level as yourself if you know what you're doing, or just get some help; there aren't many elites roaming Azeroth anymore, and the ones you do encounter are often fought with help from a quest.
Supposedly you can only play the Trial Version up to level 20 and I'm nearing it.
Meant to add that yes, you'll stop leveling at 20 while on the trial, but if you've upgraded to a full account, most of the restrictions should be lifted right away, including being able to level past 20. The social restrictions like using the AH, joining a guild, and using mailboxes can take longer to become available.