Unlocks 4 secret characters that can be accessed by first highlighting one of the two ? boxes and hitting R or L to pick a secret character: Booger Man, Earthworm Jim, High Five, and Sumo Santa.
Use a patching utility such as Lunar IPS to patch your rom.
Database match: Clay Fighter - Sculptor's Cut (USA)
Database: No-Intro: Nintendo 64 (v. 20210220-053642)
File/ROM SHA-1: 28697FBA130DED056BF7C497DEAA3E154CCE8022
File/ROM CRC32: 434DE656