Using the lava to revert the stunned blargg to its normal state shows that the blargg has a glitched animation frame that you normally dont see since its hidden behind the lava.
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https://www.youtube.com/watch?v=pqbhkAexHaM
Sometimes a block can be hit multiple times while a block factory is active.
Also I didn't knew that if you dupe the noteblock that has a star in it to the left you get a feather and to the right you get a fire flower.
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https://www.youtube.com/watch?v=xaJOFHjkXG4
If you finish a boss just as you hit a goaltape, the bonusstars flash glitched and there won't be a bonusgame.
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https://www.youtube.com/watch?v=lGICN46kHTQ
Spawning a transforming powerup on the same frame yoshi despawns. You can keep yoshi in the bonusgame, but he disapears on the overworld for some reason.
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https://www.youtube.com/watch?v=RuUH1x_YbwE
Throwing a shell upwards on the frame it is about to sink in lava will cause it to reset to it is initial state. In other words, it'll suddenly have a Koopa inside it. You can perform the above glitch with other carryable sprites by getting said sprite in slot #1 and overloading it. This will have some odd effects on the sprites when they're reset, such giving a key wings or changing a P-switch into a gold switch. Unfortunately the golden P-switch disappears after one frame.
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https://www.youtube.com/watch?v=KMMRdPhiauE