Where Blubs live
The author says Blubs commonly appear in overgrown biomes within the mod’s Sift dimension. The project names Overgrown Forests, but does not publish a Blub-specific spawn table or chance. Use the author’s latest file and world-generation notes if a particular version matters.
Soul Block interaction
Blubs are attracted to players holding Soul Blocks. The author describes a one-in-three chance to tame one using a Soul Block. This is the author’s stated mechanic for the current project description, not a measured result from our own playtesting.
After taming
A tamed Blub can follow, sit and defend its owner. Its ears droop further backward as health decreases, giving a visible state cue. The author has not provided damage or health statistics in the cited project description, so this guide does not invent them.
Version and official scope
Mielon publishes separate files for different Minecraft versions and loaders. Check the exact file and its changelog before assuming every behavior is present in your installed build. Mojang has not named Blub as a mob for the planned vanilla Sift in the cited announcements.