Lethal Lava Land

Lethal Lava Land is the seventh level in Super Mario 64 and its DS remake. When Mario gains the basement key after beating Bowser in the Dark World, he can travel into the sewers of the castle, where he'll find the portrait leading to Lethal Lava Land.

World Overview
The world consists of a large pool of lava that extends over the entire playing field. A multitude of sturdy and sinking platforms are the only things that keep Mario from falling into the deadly lava. Several bullies that roam across the stable platforms will attempt to knock Mario into the lava; they must be avoided or defeated. A large volcano resides in the middle of the stage. When it is not erupting, Mario can jump down the center to access a new sub-world. Two stars are available down here, but Mario can not exit the volcano once he enters it. It can only be exited by obtaining a star or a loss of life and enter a new world.

Stars
There are 7 stars to obtain in Lethal Lava Land. If playing on a Nintendo DS, the sixth and seventh stars will be different than in the Nintendo 64 version. Consider getting stars 5 or 6 before attempting any of the others. This way, you will be able to play those stars each time the level is revisited and you will also have access to a Koopa shell you can ride.
 * Star 1: Boil the Big Bully
 * Star 2: Bully the Bullies
 * Star 3: 8 Red Coins w/15 Pieces
 * Star 4: Red Hot Log Rolling
 * Star 5: Hot Foot It Into the Volcano
 * Star 6: Elevator Tour In the Volcano
 * Star 6: Inside the Volcano (Nintendo DS)
 * Star 7: Flaming Silver Stars (Nintendo DS)
 * Star 7: 100 Coins

Star Collection

 * Boil the Big Bully: From the starting point, long jump over the gap and then take a left and a right. Head across the puzzle pieces and head right to the bully. To obtain the star, knock the bully into the lava. This can be accomplished by jumping into him, punching him, or jump kicking him. The star will appear on a nearby platform; the platforms leading to it collapse, so be careful on your approach.
 * Bully the Bullies: Make your way to the island just past the one where the Big Bully lurked. Knock the three Bullies into the lava and when they are defeated, another Big Bully appears. Defeat him the same way you defeat the Big Bully and the star is yours.
 * 8 Red Coins: Head to the shifting platforms that have the picture of Bowser on them. Collect all 8 red coins and the star is yours. If the puzzle forms into Bowser, several coins will appear in the center of the platforms.
 * Red Hot Log Rolling: From the start of the level, head away from the bridge and the eyeball that is on the wire platform. When you reach the volcano, turn right onto the S-shaped walkway. Look around and you will see a platform with 2 Bullies on it. Head in that direction and turn right. There will be a platform by several lava shooters. Upon reaching the other side, get onto the log and roll it to the left a few times. Collect the star. Alternatively, you can use the Wing Cap near the beginning of the level and use it to fly to this star. Also, if you retrieved stars 5 or 6, you can ride the Koopa shell to this area.
 * Hot Foot It Into the Volcano: Use the Wing Cap and fly into the volcano. Follow the pathway along the wall all the way to the top to collect this star.
 * Elevator Tour In the Volcano: Head into the volcano and instead of going up the walkway, get into the elevator and take it up. A series of poles and floating platforms will assist in getting you up to the star.
 * 100 Coins: Enter the level using either stars 5 or 6. Ride the Koopa shell and surf the lava to collect as many coins as possible. Destroy the two eyeball monsters to get blue coins. Go to the island with the bullies for 8 coins and check out the rolling log area for 8 more. Do not forget to collect the 8 red coins and make sure the Bowser puzzle completes itself so you can get a few more coins. Destroy every enemy possible to collect additional coins. If you need a few more coins to finish, head into the volcano and grab the coins you need, then get the star to exit.

Nintendo DS Star Collection

 * Inside the Volcano: Go into the volcano and head the opposite way you went to collect the fifth star. You should see a moving platform; jump on it and ride it up the volcano until you see another moving platform. Speedily jump on it to avoid falling in the lava. Ride this platform up until you see a very small platform with a pole. Carefully jump from the platform to the pole to collect the star. Timing and the angle of your jump are critical - do not spend too much time on the platform or you will fall into lava.
 * Flaming Silver Stars: Use the Koopa shell in the yellow box to surf around and collect the stars. Try not to lose the shell, as it will make it very difficult, but not impossible, to get all the stars.