Out-of-bounds
From Inkipedia, the Splatoon wiki
Certain Stages in Splatoon and Splatoon 2 have Out-of-bounds areas which are not actual stage hazards (such as Water).
These are usually set when falling off tall stages or jumping over stage barriers.
When the player touches these areas, their character will disappear in a puff of smoke, after which the screen will black out before they respawn.
Trivia
- The bug in the Splatoon 2 version of Arowana Mall where dodge-rolling with Dualies or using the Splashdown would cause the player to be splatted was caused by an out-of-bounds area defined inside a wall which these actions would clip into. This bug was fixed in Version 2.3.2.