Goblin Razerunners — ruling 1

You don't count how many +1/+1 counters are on Goblin Razerunners until its triggered ability resolves.

Goblin Razerunners — ruling 2

If Goblin Razerunners leaves the battlefield after its ability triggers but before it resolves, the amount of damage it deals is equal to the number of +1/+1 counters that were on it as it last existed on the battlefield.

Goblin Razerunners : règles, fonctionnement et interactions (MTG)

Goblin Razerunners 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

, Sacrifice a land: Put a +1/+1 counter on this creature. At the beginning of your end step, you may have this creature deal damage equal to the number of +1/+1 counters on it to target player or planeswalker.

How it works : Goblin Razerunners

Original English text — Wizards of the Coast / Scryfall

#1February 1, 2009· Wizards of the Coast
You don't count how many +1/+1 counters are on Goblin Razerunners until its triggered ability resolves.
No other card is named in this ruling.
#2February 1, 2009· Wizards of the Coast
If Goblin Razerunners leaves the battlefield after its ability triggers but before it resolves, the amount of damage it deals is equal to the number of +1/+1 counters that were on it as it last existed on the battlefield.
No other card is named in this ruling.