Lava Lake Skip
Note: This page describes a glitch, trick, or exploit. To see others, click here.
Explanation
Normally, in the exterior/entrance area of Oni Island, after reaching the platform with the Golden Gate, you must jump into the lava lake below and swim across to either the East or West sections. From there, you can use an Inferno Pillar to raise Ammy out of the lake and onto the platform from which you enter the lower interior. Instead, it's possible to jump off the railing surrounding the Golden Gate platform and jump directly to the "pier" portions of the opposite platform.
Demonstration: https://youtu.be/DjCeHo3RIMU?t=40
This is generally not useful, as it's faster to beat Oni Island by performing Early Thunderstorm to skip most of the lower interior entirely.