Wario Land 64 was a ROM hack created by WROgamer2025 (AKA WarioGamer2025).
The following is/was the hack's description on romhacking.com:
This is a hack that aims to recreate what Super Mario 64 was before... a Wario Land game. It may sound crazy, but the thing is that Nintendo, after the failure of the Virtual Boy, didn't want the same for the Nintendo 64. For security, they decided to not to make a Mario game, so they made a Wario game instead. When the console was proven to be good, they realized that the console wouldn't ruin Mario so Nintendo archived Wario Land 64 and they started doing Super Mario 64.
This hack was previously deleted from this site because of the bad reviews. I have made various alternate versions of this hack so no one will give any negative reviews.
Special thanks to:
B3313 - for inspiring me for the levels
MoonJam - for the original castle areas of his cancelled Wario Land 64 hack
a bear - for the original 10th level and castle basement
E10K - for uploading the trailer and the guide I made to Youtube
JustJacob, JakeDower, and many other people - for helping me