Completely invincible as in can't despawn, can't be destroyed by explosions/lava, etc.
# Do Tinker's tools on the ground never despawn?
B:toolsNeverDespawn=true
That's news to me. Every single tinker tool that I've dropped after being killed has despawned with the rest of my gear. This isn't a new change in 1.0.7 is it?
It's possible that sneaky zombies keep stealing them and despawning I guess. But I've lost them during the day this way in desert biomes after being killed by invaders.