Thalassophobia is an expansive content mod with 30+ new items and a new elite type. Development is still ongoing, and the current mod is very rough. There will be issues or crashes, but the general effects of all the new content should work. If you want to give feedback or have any suggestions you can reach out to me on Discord @jt hehe#5756.
The Greater Wisp will die and the pop up will occur, but the item won't break and will spawn another wisp.