I'm also hearing the chickens are ready for some tricks and/or treats.
We have the full changelog from the update for you. There are more than just ghosts changed in this update, so be sure to read up.
Changelog for CS:GO for October 22, 2018
HAPPY HALLOWEEN
• In Casual, Demolition, and Flying Scoutsman game modes, players now haunt the world as ghosts when they die until the end of the round. Spoooooky!
• Ghosts can:
— Only be seen by other ghosts and observers.
— Apply Graffiti in the world.
— Affect interact-able props (soccer balls, glass, potted plants, etc).
— Turn chickens into zombie chickens.
— Possess Bots by using them.
• Two pumpkin soccer balls now spawn in a random places on the map during Halloween.
• Improved chickens ability to avoid walking straight into walls.
• Chickens now spawn in all non-competitive matches during Halloween.
• Chickens have gotten into the spooky Halloween spirit.
• Who put all this candy corn in my gun?!
MAPS
Biome
• Fixed out of map exploit
• Fixed several stuck spots
• Fixed several incorrect collisions
• Updated radar to new style
Subzero
• Minor optimizations
• Minor readability improvements
• Fixed several deathmatch spawns
• Fixed clipping texture playing wrong sound at A Pit
• T-Water no longer kills players
• Updated radar overview
Cbble
Halloween is here, so why not try out some super scary layout changes?
• Removed connector between Long A and Underpass
• Blocked long view angle from Long A CT side towards courtyard
• Decreased height of doors in Underpass
• Added window in Underpass
• Removed slanted door leading into Underpass
• Removed a large section of old Bombsite A courtyard
• Moved up Bombsite A zone towards ramp
• Removed access to most of T spawn area
• Moved up T spawn positions
• Added climbable props in dropdown
• Added cover in corridor leading to Bombsite B platform
• Added spooky Halloween theme
UI
• Added fallback image for unknown workshop maps.
• Fixed a case of incorrect player alive record keeping.
• Fixed regression in map vote random shuffle.
• Fixed voting tab not having initial focus.
• Fixed issue with early votes being ignored in some cases.
• Fixed case where end of match would flicker on future consecutive matches.
• Fixed mouse cursor appearing immediately on end of match.
• Fix for a case of bad perf with high maxrounds.
MISC
• Timeouts are now saved and restored in round backups.
HAPPY HALLOWEEN
• In Casual, Demolition, and Flying Scoutsman game modes, players now haunt the world as ghosts when they die until the end of the round. Spoooooky!
• Ghosts can:
— Only be seen by other ghosts and observers.
— Apply Graffiti in the world.
— Affect interact-able props (soccer balls, glass, potted plants, etc).
— Turn chickens into zombie chickens.
— Possess Bots by using them.
• Two pumpkin soccer balls now spawn in a random places on the map during Halloween.
• Improved chickens ability to avoid walking straight into walls.
• Chickens now spawn in all non-competitive matches during Halloween.
• Chickens have gotten into the spooky Halloween spirit.
• Who put all this candy corn in my gun?!
MAPS
Biome
• Fixed out of map exploit
• Fixed several stuck spots
• Fixed several incorrect collisions
• Updated radar to new style
Subzero
• Minor optimizations
• Minor readability improvements
• Fixed several deathmatch spawns
• Fixed clipping texture playing wrong sound at A Pit
• T-Water no longer kills players
• Updated radar overview
Cbble
Halloween is here, so why not try out some super scary layout changes?
• Removed connector between Long A and Underpass
• Blocked long view angle from Long A CT side towards courtyard
• Decreased height of doors in Underpass
• Added window in Underpass
• Removed slanted door leading into Underpass
• Removed a large section of old Bombsite A courtyard
• Moved up Bombsite A zone towards ramp
• Removed access to most of T spawn area
• Moved up T spawn positions
• Added climbable props in dropdown
• Added cover in corridor leading to Bombsite B platform
• Added spooky Halloween theme
UI
• Added fallback image for unknown workshop maps.
• Fixed a case of incorrect player alive record keeping.
• Fixed regression in map vote random shuffle.
• Fixed voting tab not having initial focus.
• Fixed issue with early votes being ignored in some cases.
• Fixed case where end of match would flicker on future consecutive matches.
• Fixed mouse cursor appearing immediately on end of match.
• Fix for a case of bad perf with high maxrounds.
MISC
• Timeouts are now saved and restored in round backups.
Isn't this something that can be done already? I don't play too much anymore, but I thought this was a thing. Oh well, interesting Halloween update.