Gensokyo/Kisume

Kisume is a Pre-Hardmode miniboss. She attacks players who trigger certain pressure plate traps which are encountered in the underground and cavern layers, but not in the areas where the underground part of the world's evil biome was initially generated.

The amount of Kisume traps that is generated depends on the map size:
 * Small World: 25 traps
 * Medium World: 38 traps
 * Large World: 50 traps
 * Modded Map Size: Map width in blocks * 0.006. Result rounded down to the next integer.

Behavior
Kisume will initially ambush the player by dropping down from above. Afterwards, she will cycle through four phases:
 * Throwing bones and skulls at the nearest player
 * Moving up the shaft she is situated in while spawning will-o-wisp projectiles
 * Waiting for a small duration
 * Dropping down again

While dropping down, Kisume's damage is proportional to her velocity; at her maximum velocity, she does 140 / damage on contact.