Hidden in each World of Paper Mario: Sticker Star are some hidden boxes which allow you to upgrade any attack sticker in your possession: just like with the Secret Blue Doors you’ll need to paperize a sticker inside an outline, red in this case, to make a block appear, with the upgraded sticker inside. Be careful that you can only use small stickers since they have to fit inside the block’s outline. Upgrade blocks also reset every time you exit the level so you can use them multiple times.
1-1
The first upgrade block is above the tree stump to the right of the bridge; the second one is within a circle of flowers right past the first block.
1-4
Keep going right after the windmill and you’ll encounter another circle of flowers: the ugrade block is in the middle of it.
1-5
Near the final boss location there’s a column: in the center is your upgrade block
2-1
There are four upgrade blocks in this stage: to reach the first one first head north and then east, you’ll reach a slope with the block on top. For the second block get to the east of the previous area and east again: to the right of this area you’ll see the block near two other item blocks. For the third upgrade block go to the northeast from the location of the second block, climb the pyramid and jump over the gap. The final block is in the same area as the first block: get between the two cactuses to reach a hidden room below.
2-2
Near the exit to the Sphynx there should be a circular room: the block is in this room
2-4
In the zone with all the holes, get to the right, right and then left and left again. Enter the room and the block will be there.
2-5
On the second floor there’s a ruined column: the block is here
3-1
This upgrade block is hard to miss since it’s close to the save block in this stage
3-2
Five block await you in this stage and they’re pretty close to each other. For the first one head north, northeast, northwest and then northeast twice. For the second head from the first block head southwest then up and to the right. For the other three blocks head first to the northeast, then to the north and to the northeast.
3 – 4
Another hard one to miss: go to the right at the beginning of the level and in the next area you’ll fine the upgrade block near the exit
3 – 5
At the beginning of the stage there’s a platform right in the middle of the first area, with the block on it
3 – 7
Another block you can’t miss: it’s in the prison with the web holding the Wiggler segment
3 – 9
Another easy one: from the beginning area go right and then up.
3 – 12
In the area where you’ll fight the boss head to the right and you’ll find the block outline
4 – 1
From the beginning, head right twice: you’ll see a ring of flowers with the block in the middle
4 – 2
In the last area of the stage, to the left there are four hidden tree stumps with 4 upgrade blocks
4 – 3
On the kitchen table is a pink flower: the block is directly over the flower
4 – 6
While on the upper railway you’ll see a group of blocks with the upgrade block
5 – 1
The first stage of world 5 has 6 total upgrade blocks: the first one is in the middle of the pink flower near the beginning. The second one is to the right of a giant flower in the same area as the first block. The other four blocks are to the right of the trash pile: you’ll find a hidden area with four tree trumps and four upgrade blocks.