Flying Wither Spider [Nether Mob]

You heard me.

Abilities: Like a regular spider, but it can fly like a phantom, and it inflicts the wither effect on a hit. Is also immune to fire and poison and such.

Appearance: Like a regular spider, but with wings, and a new texture as appropriate for the nether.

Behavior: Would be neutral towards all mobs except Striders, which they constantly hunt. Would have similar combat tactics to a phantom.

Spawning: Spawns occasionally on any surface within 50 blocks of an existing strider, except in a Warped Forest biome or a Basalt Deltas biome. Would have a 1% chance of spawning as a Wither Skeleton Jockey. Can also spawn on wither roses.

Drops: Spider eyes, string, and coal. Could potentially drop Fermented Spider Eyes instead of regular Spider Eyes.

Purpose: Would be a challenge to players that ride striders in the Nether. Would also be a cool environmental "hazard" to watch from afar, and would be a source of string and coal in a Nether Survival game.