Unagi secret in New Super Mario Bros. (WARNING: SCARY)
"Unagi secret in New Super Mario Bros. (WARNING: SCARY)" is a satirical video by Kjolt uploaded on February 8th, 2026. Like the videos before it, starting with "secret HOLY CRAP room found in New Super Mario Bros.", it is a parody of old YouTube videos showing off video game hoaxes, as well as modern videos aiming to emulate the "horror" of these hoaxes in the form of ARGs. It is the third installment of the "scary mario secrets" playlist, releasing after the longest gap between these videos to date. It is also the longest video in the series, being over 8 minutes long.
The background music for this video is "Dreamscape" from the 009 Sound System, a song popularly used around the era these videos are based on.
Unagi Secret
Unlike previous videos, the player in this video is not actively seeking a secret. Instead, the secret slowly seeps into the level being played, 8-3. During the first playthrough, Mario is defeated by a Unagi (now known as Maw-Rays in modern games) due to the player trying to "prank" it. Upon re-entering the course, the background has shifted from the typical underwater cave to that of an ordinary underground area. However, no attention is drawn to this as the more notable change is the fact that multiple Unagis are now swimming away from their original positions, and some elements and enemies are missing from the course. the Mega Unagi, which is usually the main feature of the level. The level is played casually and normally, although the player comments on the odd changes that have taken place.
When the player reaches the red exit pipe, they are not warped to the flagpole area. Instead, they are sent back in the same second half of the level, which has undergone drastic changes. The timer which was just at 128 is now 256, the background has become darker and the water effect is static, and the music is replaced with dripping ambience. The right side is blocked by a wall of brick blocks, and an arrow sign points left. When Mario swims in that direction reluctantly, metal blocks spell out the phrase "GET OUT". Just past this, the Mega Unagi is triggered to swim out of its cave like usual. Miraculously, the player hits an invisible ? Block containing a Super Star, and uses its invincibility to phase through the Mega Unagi as it breaks the wall ahead. For the remainder of the level, it has been further stripped of features, only inhabited by a few Unagis. There are now additional metal blocks obstructing the tunnel, and two blocks preventing Mario from exiting the level. As Mario traverses this area, an ominous reverberating noise can be heard echoing in the background. When the Mega Unagi respawns, it defeats Mario.
The player tries again, this time entering the same area simply by going into the surface entrance. This time, they dodge the Mega Unagi as Mini Mario instead of using the Super Star. The ominous background noise plays again, this time in a lower pitch. Just as the player reaches the end, the Mega Unagi returns again accompanied by a louder, higher-pitched version of the noise. When Mario is defeated, the game briefly glitches as if freezing, but then resumes as normal when Mario is returned to the world map.
Reception
While it did not perform well in the first few days, this video ultimately surpassed the first video in the series after just over a week of being uploaded. However, it does not match the same height of likes and comments per view as the HOLY CRAP room; interestingly, there was a noticeable increase in the frequency of critical comments. Some commenters took issue with the "forced" nature of the video, interpreting that it aimed to be more faithful and scary than it turned out to be. Despite these few people online missing the damn point, the video was generally quite well-received.