<p>There is no specific cooldown for this mini world change to be activated. This has been shown by this <a rel="nofollow" href="https://tibia.fandom.com/wiki/TibiaWiki:Bosses_Spawn_Frequency">TibiaWiki's research article</a>. If you check the plot for e.g. Elvira Hammerthrust, you'll see that it can spawn two days in a row or take many days to spawn again. The same is valid for the combined data of all 4 "bosses". </p><p><img alt="" src="https://tibia.fandom.com/wiki/Special:Filepath?file=Spawn Frequency - Elvira Hammerthrust.png"></p><p></p>src="https://vignette.wikia.nocookie.net/tibia/images/8/81/Spawn_Frequency_-_Elvira_Hammerthrust.png/revision/latest?cb=20200210211529&path-prefix=en" style="height:400px; width:800px"></p><p></p>