The Meadow (https://legacy.atrocity-pets.com/pages/view/meadow/)is an area on the east side of the world map. You can explore the Meadow if you have a Homegrown Carrot (bought from Farmed Foods (https://legacy.atrocity-pets.com/shop/browse/Farmed%20Foods) during the Season of Leaves or found by digging (https://legacy.atrocity-pets.com/exploremeadowfarm) at the Meadow Farm (https://legacy.atrocity-pets.com/meadowfarm)).
(https://legacy.atrocity-pets.com/picuploads/inkarnatemaps/meadow.jpg)
The rivvid tunnel (https://legacy.atrocity-pets.com/burrowentrance) is a special area at the top-left corner of the Meadow (https://legacy.atrocity-pets.com/meadow/). Looks like you need to get past him to get in.
More info on Rivvid tunnel (https://legacy.atrocity-pets.com/mybb/showthread.php?tid=193)
(https://legacy.atrocity-pets.com/picuploads/rabbitburrow/bigwigsentry.png)