Undercity Uprising — ruling 1

Remember that a source with deathtouch has to deal damage, but not necessarily combat damage, to destroy another creature. As long as the fighting creature you control has power greater than 0 (and the damage isn’t prevented), the fighting creature you don’t control will be destroyed.

Undercity Uprising — ruling 2

If one of the two target creatures is an illegal target by the time Undercity Uprising tries to resolve, no creature deals or is dealt damage. Creatures you control still gain deathtouch.

Undercity Uprising — ruling 3

If both target creatures are illegal targets by the time Undercity Uprising tries to resolve, the spell doesn’t resolve. No creatures deal damage or gain deathtouch.

Undercity Uprising — ruling 4

The first part of Undercity Uprising’s effect affects only creatures you control at the time it resolves. Creatures you begin to control later in the turn won’t gain deathtouch.

Undercity Uprising : règles, fonctionnement et interactions (MTG)

Undercity Uprising is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Creatures you control gain deathtouch until end of turn. Then target creature you control fights target creature you don't control. (Each deals damage equal to its power to the other.)

How it works : Undercity Uprising

Original English text — Wizards of the Coast / Scryfall

#1October 5, 2018· Wizards of the Coast
Remember that a source with deathtouch has to deal damage, but not necessarily combat damage, to destroy another creature. As long as the fighting creature you control has power greater than 0 (and the damage isn’t prevented), the fighting creature you don’t control will be destroyed.
No other card is named in this ruling.
#2October 5, 2018· Wizards of the Coast
If one of the two target creatures is an illegal target by the time Undercity Uprising tries to resolve, no creature deals or is dealt damage. Creatures you control still gain deathtouch.
No other card is named in this ruling.
#3October 5, 2018· Wizards of the Coast
If both target creatures are illegal targets by the time Undercity Uprising tries to resolve, the spell doesn’t resolve. No creatures deal damage or gain deathtouch.
No other card is named in this ruling.
#4October 5, 2018· Wizards of the Coast
The first part of Undercity Uprising’s effect affects only creatures you control at the time it resolves. Creatures you begin to control later in the turn won’t gain deathtouch.
No other card is named in this ruling.