World 4-Tower (New Super Mario Bros.)
From the Super Mario Wiki
This level is filled with lava. Mario should jump on the moving gray blocks to get to the door. In the next area, lava rapidly rises. First, Mario must get on the other side of the metal fence. If the player stays to the left, they eventually reach the first Star Coin. The second Star Coin is in between a few Amps. Next, Mario should avoid the spikes, and continue climbing. If Mario stays to the right, then he can find the last Star Coin. A Red Ring is found near the end of the level. At the top of the tower, there are double doors that lead to Bowser Jr. This time, Bowser Jr. is harder to defeat. If the player tries to jump on him, he goes inside his spiky shell. Mario should wait until he throws a Green Shell. Then, Mario should jump on the shell to stop it, and he should throw it back at Bowser Jr., which knocks him him over, making him vulnerable to jumps. Mario must repeat the process three times to defeat Bowser Jr.