Barzer's Fog Cloud Bat: Splitting the Battlefield in Two
Before the cave assault, Barzer lays out a full tactical briefing: position the bat familiar at 10 feet, cast fog cloud, blind everything above while the party fights freely below.
Some players enter a room. Some players divide it.
Before the party moves into the cave, Barzer stops everyone and runs the plan. His bat familiar floats exactly 10 feet off the ground — the same height as the goblin archers perched on the cave ledges. Cast Fog Cloud centered on the bat at that exact elevation. The spell creates a horizontal wall of obscurement: everything above it is blind, everything below is not. The goblins at ground level are visible and can be engaged freely. The ogres, and anything lurking near the ceiling, are fighting with disadvantage.
Once the party engages and gives away position, those blinded enemies still can't see them clearly. The plan holds for the duration of the fight. "An hour for fog cloud?" Reece asks, disbelieving. An hour.
One bat. One spell. Two separate battles. Barzer had already won before the party walked through the door.
Barzer's Fog Cloud Bat: Splitting the Battlefield in Two