Potion of Speed

We once had a session where another player was allowed to stack these with the exception that he had to roll an ever increasing D100 as he ran the risk of a heart attack. He ended up killing everything hostile then running so fast he went back in time.

Bro became Barry Allen

Step by step guide on how to become the fastest man in dnd:

1. Get a potion of speed, a potion of watchful rest, and some protective gear along with some way to cast detect poisons and disease

2. Mix the two potions, if it explodes, turns into poison, or you take "a little taste" and the potion of speed is no longer active restart from the beginning, 15% if your dm is nice, 25% if your dm is mean, and 20% if your dm just does a coin flip. keep on doing this until you test that the speed potion is permanent, 1%.

3. Mix with potions of watchful rest until you get your desired doubling of effects, I would recommend a magnified effect of ~4-8, if it explodes, turns into poison, or the potion of speed is no longer active restart from the beginning. Doubling the effects has a 9% chance of happening, halving the effects has a 10% chance of happening, and no change to the effects has a 55% chance of happening.

4. Drink your million gold coin potion and gain permanent 8x speed, a +8 to AC, advantage to Dex saves, and 4 extra actions that can be used to take the attack(1 attack), dash, disengage, hide, or utilize action. An average character can now travel 240 feet without trying and up to 1200 feet per turn.(calculations done with a 4x multiplier)

If your dm allows you to use heroic inspiration to do this I would highly recommend it but everything above is RAW and the choices made wile creating this reflect that.

*WARNING: DRINKING ANY OTHER POTIONS AFTER CONSUMING THIS ONE COULD LEAD TO DEVASTATING RESULTS*