Adds a new vanilla friendly entity in the end which can be used to respawn, I typed instructions on how to use them below but tbh you can just follow vanilla advancement system through regular gameplay and figure it out for yourself lol
The first step to setting your respawn point is obtaining trimmed chorus flowers, these can be obtained easily by right-clicking on chorus flowers with shears (this would take a lot of durability though)
After trimming it you need to "tempt" a rippler into "activating" for you, ripplers will follow you if you have chorus fruit in your hands. Ripplers will also naturally go to the trimmed chorus flowers if they're within a distance, if they're bound to a trimmed chorus flower then they won't be able to be used with chorus fruit anymore. This process might take a few tries but overall it is easy to get them on.
After that right-click on the trimmed chorus flower, and you can now respawn on it as long as your rippler is alive and the block isn't broken :>. You can't heal ripplers directly but they heal when they're bound to a trimmed chorus flower. Each respawn has a 1 in 10 chance to break the trimmed chorus flower as well so might want to watch out for that and make sure your rippler doesn't run off when it breaks
