Acme Box

The Acme box is a plywood box, about 1m², with "Acme" written in bold red letters on each side. It can be bought in general stores, or any store that supplies boxes, for 150-400 gold pieces. The box has 20 uses and, no matter the effect of what's inside, can't be destroyed by any of it's effects. When a player opens the box have them roll a d20. Each affect of the box can only happen once so reroll if you land on one that's already happened. The effects only harm or benefit the player who opened the box. If the box makes an enemy it targets only the player who opened it. If another player or creature targets the enemy the box summoned then a second version of that enemy manifests and targets only its aggressor. The inside of the box has no discernible features.

 1 - The box produces a blinding light. If the player fails on a DC13 Con check they're blinded for five of their turns. At the beginning of each of their turns they can reroll the check. If they succeed the condition is removed. If they fail, the condition persists until the effect naturally ends or the player succeeds on the saving throw at the beginning of their next turn.

2 - The box produces a green "Bat-Man" outfit. The outfit covers the creature who opened the box and goes over armor and clothing. While worn, the outfit gives a 5ft fly speed (hover). The outfit has wings that attach to the upper arms and calves of the creature. Next time the creature takes damage the inside of the wings fall out and the creature loses it's fly speed, but the frame of the wings remain attached. It takes an action to remove the outfit. 

3 - The box produces a giant rubber band that, when attached to two objects, immediately brings them together with enough force to deal 4d10 bludgeoning damage. This can be changed at your DM's discretion depending on the size of the objects.

4 - An explosion comes out of the box. The opener takes 2d6 fire and 2d6 force damage and is blown back 10ft. The box is unharmed.

5 - When the box is opened a loud whistling begins that gets higher the longer it goes on for. After two rounds an anvil falls from the sky onto the opener. The opener is flattened and takes no damage but is considered as prone with disadvantages on attack rolls it makes but advantage on attack rolls against it.

6 - The box either produces 12 spiders or two giant spiders. The opener decides.

7 - The box produces a 100ft long rope that, when attached to two things and pulled, pulls the further one closer. This can be used on anything, but only once. For example, if its attached to the ends of two cliffs it and is pulled on it will bring the further cliff closer.

8 - Two rounds after the box is opened a piano falls on the head of the opener, dealing 4d10 bludgeoning damage and breaking on impact. The piano makes a Bm (b minor) chord when it lands.

9 - The box produces a pogo stick with dynamite on the end. The pogo stick bounces 10 times using the explosion of the dynamite directly into the nearest hazard, be it a wall, cliff, spikes, or anything else.

10 - The box produces a bird costume (opener's choice) which immediately attaches itself to the opener. The opener is then targeted by five Giant Hyenas.

11 - The box produces Acme glue, making a 30ft area around it difficult terrain for 1 minute.

12 - The box produces a pair of rocket shoes that attach themselves to the opener. Next time the opener moves they move 100ft uncontrollably in the direction they attempted to move until they either hit an object or hit the 100ft mark.

13 - The box produces a boomerang covered in glue except for one end. When thrown, the glue drips onto the hand of the thrower and they go with the boomerang.

14 - The box produces Acme axel grease, covering a 30ft area around it. Whenever a creature does anything in this radius they move 3ft. If they take damage they're knocked prone.

15 - The box produces a handsaw that when used makes everything but the area it cut fall. For example, if you cut a circle in a bridge attached to two cliffs, the cliffs and the bridge fall while the circle floats.

16 - The box produces a piece of paper with a generic fact or statement on it. It ends with "This note will explode in three seconds." It explodes next time any creature does anything or after three seconds outside of combat.

17 - A coyote and a road runner pass by. Nothing else happens. They come from nowhere and seemingly disappear when no one looks at them anymore.

18 - When the box is opened 24 cows fall from the sky in a 20ft radius around the box. Each cow deals 1d10 bludgeoning damage and any creatures that start their turn in the radius or enter the radius during their turn must make a DC15 Dex save or be hit by a cow. This can only happen four times a turn. After six rounds the cows stop falling. They fall four at a time.

19 - A gramophone comes out of the box on a piston and begins to play a song of the DM's choosing. Once the song ends the piston retracts into the box. The piston doesn't seem to have a source.

20 - The box produces one copper piece.

When all the possibilities of the box have been rolled, it crumbles into pieces leaving behind a sign that says "Thanks for buying! -Acme." In fine print, it also says "By reading this sign you've waived all rights to sue us for anything."