I just checked the translation for おれより下のやつたこ, and it said "Tako below me", and I got a perfect name for this Japanese player. "Taker Baloney"

The player who submitted this is well known within the MK8DX time trial community, he used to go by Itakura (いたくら), but now goes by Obito. He is the WR holder for grumble volcano on 150cc. He requested that his submission on the leaderboard use the name "おれより下のやつたこ" however so that is why his name appears as this.

Where did you find the Japanese phrase “Tako below me?”

Google Translate, if I had to guess.

Actually, scratch that. I checked it myself, and it gave me "The octopus below me" XD

I got it from Microsoft translate on Edge.

No digital translators are completely accurate lmao