Phantoms become a Mountaintop Mob

Idea: Phantoms only attack above a certain height and spawn more in mountains.

Part of the original Phantom mob concept seemed to be that they would be a risk primarily to players in high, unsecured locations like cliffs, mountains, treetops, block towers. Currently they rarely if ever perform that function as they are either encountered most often in the lowlands or , but as caves and cliffs part 2 will focus on cliffs and mountains in part, it seems like a good moment for synergy between old and new features.

So: Phantoms spawn as currently, but at higher altitude, and only begin attacking players if they were above a certain y level or travel above it. Then Phantoms would primarily attack players in the mountains, at the tops of tall jungle and giant spruce trees, and in high elevation builds. This would reduce the motivation among players to sleep constantly or turn off phantoms, and add an interesting, unique element of danger to mountains. Perhaps they could spawn more frequently in mountains, or seek shelter in mountain caves during the day when spawned.