Spider Skeeter Anomaly

Spider Skeeters are uncommon anomalies that may be found in Super Mario 64's Wet-Dry World. They are a variant of the Skeeter enemy that almost always entirely replaces regular Skeeters. Spider Skeeters, as the name suggests, are Skeeters that resemble spiders, having 8 legs and becoming dark grey. This anomaly most commonly appears when the player jumps into the highest point possible in the Wet-Dry World painting on their first playthrough.

Behavior
Spider Skeeters are typically described as acting differently to regular Skeeters. They still glide along the water, but they stop after each stride to look around the level and rotate in situ. When the player swims near them, they chase after them. On land, they walk around aimlessly until the player draws near, which will make them rush towards the player to attack them. It is worth noting that they speed up when chasing the player.

Theorizing
The currently accepted explanation for this anomaly is that this is the result of the Personalization A.I. trying to make the Skeeter enemy more difficult, as difficulty control is one if it's main motives for changing the game. However, Spider Skeeters also appear in copies with a relatively low Wario Approximation, so this explanation is contested by some. Most people explain this by simply saying that the A.I. isn't perfect and hasn't properly assessed the player's skill. Though, in copies where Spider Skeeters do properly appear in a more difficult setting, it may have fixed this issue with the Self-Patching Anomaly.

Their dark-grey color may be a sign of Enemy Discoloring, or the enemy could be an unused enemy, which is possible due to the fact that the Personalization AI mainly runs on unused content.