The bulk update request #5491 is pending approval.
create alias sonic-oc-female (0) -> fan_character (139930)
create alias sonic-oc-male (0) -> fan_character (139930)
create alias sonic_original_character (0) -> fan_character (139930)
create alias soniccharacter (0) -> fan_character (139930)
create alias sonic_oc_character (0) -> fan_character (139930)
create alias sonicfancharacter (0) -> fan_character (139930)
create alias sonic_character (0) -> fan_character (139930)
create alias sonic_world_adventure (1) -> sonic_unleashed (1836)
create alias sonic_the_hedgehog_(archie_comics) (0) -> sonic_the_hedgehog_(archie) (12353)
Reason: Some tags relating to Sonic The Hedgehog that I think are either irrelevant or redundant to have. Looking at the sources of the posts featuring them, most of them were probably created by copy-pasting tags from places like FurAffinity or Inkbunny, where the tagging is a lot more "freestyle".
The list features tags that are in use, or might be used in the future.
Reasons for aliasing
sonic-oc-female, sonic-oc-male, sonic_original_character, soniccharacter, sonic_oc_character, sonicfancharacter and sonic_character all refer to a fan_character in the Sonic The Hedgehog style. The tags don't refer to any specific character, and considering sonic_fan_character is long aliased to fan_character, so i don't see why these ones shouldn't be aliased away as well.
sonic_the_hedgehog_series is a redundant tag, since we already have sonic_the_hedgehog_(series). Has already been aliased.
sonic_world_adventure is an alternate name for sonic_unleashed for JP markets.
There are also two tags that I've excluded from the script: sonic_adult and sonic_-_adult. I don't exactly know what to do with these, as they could mean two different things (Adult/NSFW content featuring Sonic characters, or Sonic characters as adults).
Updated