World 12-3 (Super Mario Maker for Nintendo 3DS)
From the Super Mario Wiki
World 12-3 is the third level of World 12 of Super Mario Challenge from Super Mario Maker for Nintendo 3DS.
At the beginning, there is a Pipe that spits out Fire Koopa Clown Cars. Above are two Koopa Paratroopas carrying Bill Blasters; all which guard some coins. More coins are then encountered, followed by two Koopa Paratroopas, one of which is carrying a cannon. To the right of them are Cannons and Burners and a Super Mushroom; while above are Koopa Troopas and a POW Block which knocks them all down at once. Over a bit are two Koopa Paratroopas carrying Fire Piranha Plants. The first section ends with two Cannons and a Burner. After destroying Hard Blocks with the Fire Clown Car, the player must leave it to go past a hole which it cannot past. Nearby is a ? Block containing a Super Mushroom on a Fire Flower. Above is a 1-Up Mushroom in a Hidden Block. Continuing on, there is a Galoomba inside a Fire Koopa Clown Car and another Pipe the spits Fire Koopa Clown Cars. This next section has many Koopa Paratroopas, many of which are carrying an enemy. Bullet Bills and Rocky Wrenches are on top of ground and Hard Blocks. There is another POW Block, but this is surrounded by Hard Blocks. After this are Grinders on tracks, a Fire Bar, and Bloopers, one of which is a Blooper Nanny. The second section ends with more Hard Blocks and the player must jump out towards the tiny hole in the top. The third section begins with a Fire Koopa Clown Car on a track. Past a Donut Block to the left is a ? Block with a Super Mushroom on a Fire Flower. To the right is a POW Block which must be used to take out Fire Piranha Plants to get to coins on tracks. Below, the path to the Goal Pole, though it is blocked by Big enemies and Hard Blocks. The player can also pick up a Super Mushroom on a Fire Flower and this has wings. To get to the subarea, the player must have Fire Mario to break Hard Blocks and Fire Bars guarding it. There is a Hidden Block near the Warp Pipe, too. In the subarea, the player can hit a ? Block to get a Super Mushroom on a Fire Flower and get a Fire Clown Car before a fight with Big Bowser Jr. in a Fire Koopa Clown Car. After defeating him, the player can get the last 1-Up Mushroom. After taking the Pipe, the player falls down to the Goal.
Strangely, the first two sections and the sub area don't need the Fire Koopa Clown Car save to get past Hard Blocks at the end of the first two sections.