A memory chip is an item in Kaiba.
Memory chips are small metallic cones about the size of pencil erasers. In the Kaiba universe, memories can be extracted from an individual's body and transferred into chips. Individuals with chips can alternate bodies during life and be transferred into a different body if their own dies. Specific memories (i.e. knowledge of history, "happy memories," etc.) can be transferred as well, creating a market for buying and selling memories and bodies.
As stated in Kaiba's intro only the privileged are able to use this technology leisurely; many individuals sell their memories or bodies out of necessity or spend their entire lives saving money to purchase memory chip or replacement body for themselves or loved ones.
When an individual without a chip dies, roe is released from their body.
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