Ultima Online has included some well known Easter eggs throughout the years.
* Lord British's throne is the top half of the Ultima Online logo.
* On rare occasions, casting the spell energy vortex will summon a purple llama instead of the purple cloud-like creature the spell is meant to summon. The purple llama is labeled in-game as "an energy vortex" and has the same powers as the creature the spell is named for.
* A monster called a slime existed in-game which is a small slithering blob. Some years ago on rare occasions, it was possible to encounter a slime that was renamed a "jwilson," which was purportedly named after magazine editor Johnny Wilson, who had given Ultima Online a bad review and thus earned a derisive place in the game by the developers.
* Cows may be tipped by clicking on them numerous times.
* Occasionally, an aggressive "mad cow" will be spawned in place of a docile cow.
* Walker the legendary Ranger trainer, an NPC trainer in New Haven, looks suspiciously like Chuck Norris, with references to Walker Texas Ranger in his dialog boxes.