Megaflash Stickers are the rarest and most powerful battle stickers in the game, but each one will only ever appear in one set location, (except the Megaflash Hurlhammer, which appears in two) and some can be very tricky to find. However, once you know where to find one, you can get as many as you want, so it helps to know where they all are.

Item	Location
Megaflash Baahammer	World 5-4: On the third floor, through a warp pipe hidden to the right of the moving platforms in the main room.
Megaflash Burnhammer	World 5-5: In the first area, in a secret room behind a rock near the entrance to the second area.
Megaflash Chillhammer	World 4-6: On a platform in the second minecart area that requires you to Paperize the rail to reach.
Megaflash Clone Jump	World 5-6: On the third floor, pound the stake furthest to the right.
Megaflash Eekhammer	World 5-4: At the beginning of the level, release the raft by hitting the stake with the hammer, then ride it to the right.
Megaflash Hammer	World 2-2: Behind a secret panel below the balcony in the room with the Hammer Bros.
Megaflash Hopslipper	World 5-4: In the same room as the Megaflash Baahammer and Megaflash Hurlhammer.
Megaflash Hurlhammer	World 5-1: Behind the Hammer Bro in the area with the second red flower.
Megaflash Hurlhammer (2nd location)	World 5-4: In the same room as the Megaflash Baahammer.
Megaflash Infinijump	World 5-3: In a secret area to the right of the pillars in the room with the Comet Piece that's accesible from the "loop" in the river.
Megaflash Iron Jump	World 5-5: In the fifth area, under the "X" at the top of the hill. Stand on it until you see a shadow, then move out of the way.
Megaflash Jump	World 6-2: Through the Secret Door, in the ship's cabin.
Megaflash Line Jump	World 4-6: On a ledge below and to the right of where you fight the boss. Return after getting the Royal Sticker.
Megaflash Slaphammer	World 5-5: In the fourth area, under the "X" on the ground closest to the entrance. Stand on it until you see a shadow, then move out of the way.