One of the things I like about Super Mario Bros Deluxe is how artwork for Mario and Luigi are different for each brother for winning and losing Vs. Game mode/You Vs. Boo mode, and of course 100% clearing Challenge Mode. Since Oxnard is Hamtaro's first friend and personally, I found him to be close to Luigi's cowardly personality, I had him playing the role of this character. Here he is receiving a medal from Princess Bijou for completing Challenge Mode!
Source: Source: https://www.spriters-resource.com/game_boy_gbc/smbdeluxe/sheet/31803/