As with any good chase scene, complications can arise to make a chase more pulse-pounding. The Urban Chase Complications table and the Wilderness Chase Complications table provide several examples.

Complications occur randomly. Each participant in the chase rolls a d20 at the end of its turn. Consult the appropriate table to determine whether a complication occurs. If it does, it affects the next chase participant in the initiative order, not the participant who rolled the die. The participant who rolled the die or the participant affected by the complication can spend inspiration to negate the complication.

Characters can create their own complications to shake off pursuers (for example, casting the web spell in a narrow alleyway). Adjudicate these as you see fit.

Complication:
d20 = 9

An overzealous guard (see the Monster Manual for game statistics) mistakes you for someone else. If you move 20 feet or more on your turn, the guard makes an opportunity attack against you with a spear (d20 + 3 to hit; 1d6 + 1 piercing damage on a hit).

Complication
d20Complication
1A large obstacle such as a horse or cart blocks your way. Make a DC 15 Dexterity (Acrobatics) check to get past the obstacle. On a failed check, the obstacle counts as 10 feet of difficult terrain.
2A crowd blocks your way. Make a DC 10 Strength (Athletics) or Dexterity (Acrobatics) check (your choice) to make your way through the crowd unimpeded. On a failed check, the crowd counts as 10 feet of difficult terrain.
3A large stained-glass window or similar barrier blocks your path. Make a DC 10 Strength saving throw to smash through the barrier and keep going. On a failed save, you bounce off the barrier and fall prone.
4A maze of barrels, crates, or similar obstacles stands in your way. Make a DC 10 Dexterity (Acrobatics) or Intelligence check (your choice) to navigate the maze. On a failed check, the maze counts as 10 feet of difficult terrain.
5The ground beneath your feet is slippery with rain, spilled oil, or some other liquid. Make a DC 10 Dexterity saving throw. On a failed save, you fall prone.
6You come upon a pack of dogs fighting over food. Make a DC 10 Dexterity (Acrobatics) check to get through the pack unimpeded. On a failed check, you are bitten and take 1d4 piercing damage, and the dogs count as 5 feet of difficult terrain.
7You run into a brawl in progress. Make a DC 15 Strength (Athletics), Dexterity (Acrobatics), or Charisma (Intimidation) check (your choice) to get past the brawlers unimpeded. On a failed check, you take 2d4 bludgeoning damage, and the brawlers count as 10 feet of difficult terrain.
8A beggar blocks your way. Make a DC 10 Strength (Athletics), Dexterity (Acrobatics), or Charisma (Intimidation) check (your choice) to slip past the beggar. You succeed automatically if you toss the beggar a coin. On a failed check, the beggar counts as 5 feet of difficult terrain.
9An overzealous guard (see the Monster Manual for game statistics) mistakes you for someone else. If you move 20 feet or more on your turn, the guard makes an opportunity attack against you with a spear (d20 + 3 to hit; 1d6 + 1 piercing damage on a hit).
10You are forced to make a sharp turn to avoid colliding with something impassable. Make a DC 10 Dexterity saving throw to navigate the turn. On a failed save, you collide with something hard and take 1d4 bludgeoning damage.
11–20No complication.