The Mycotyrant — ruling 1

The ability that defines The Mycotyrant's power and toughness works in all zones. As long as The Mycotyrant is on the battlefield (and still a Fungus, or somehow a Saproling), that ability will count The Mycotyrant itself.

The Mycotyrant — ruling 2

If you control a creature that is both a Fungus and a Saproling, it counts only once for The Mycotyrant's middle ability.

The Mycotyrant — ruling 3

Some cards refer to a player who has "descended this turn." This means that a permanent card has been put into that player's graveyard from anywhere this turn.

The Mycotyrant — ruling 4

Some cards refer to the number of times a player descended this turn. Those cards care about the number of permanent cards put into that player's graveyard from anywhere this turn.

The Mycotyrant — ruling 5

In either case, it doesn't matter if those cards are still in that player's graveyard.

The Mycotyrant — ruling 6

A permanent card is an artifact, battle, creature, enchantment, land, or planeswalker card. Tokens are not cards, and while tokens are put into the graveyard before ceasing to exist, that action doesn't count as a player having descended.

The Mycotyrant — ruling 7

Multiple cards have abilities that begin with "At the beginning of your end step, if you descended this turn." These cards don't need to have been under your control at the time you descended. For example, if a permanent card is put into your graveyard during your first main phase and you cast Stalactite Stalker your second main phase, its ability will trigger at the beginning of your end step.

The Mycotyrant — ruling 8

Abilities that begin with "At the beginning of your end step, if you descended this turn" will trigger only once during your end step, no matter how many times you descended this turn. However, if you haven't descended this turn as your end step begins, the ability won't trigger at all. It's not possible to put a permanent card into your graveyard during the end step in time to have the ability trigger.

The Mycotyrant : règles, fonctionnement et interactions (MTG)

The Mycotyrant 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

Trample The Mycotyrant's power and toughness are each equal to the number of creatures you control that are Fungi and/or Saprolings. At the beginning of your end step, create X 1/1 black Fungus creature tokens with "This token can't block," where X is the number of times you descended this turn. (You descend each time a permanent card is put into your graveyard from anywhere.)

How it works : The Mycotyrant

Original English text — Wizards of the Coast / Scryfall

#1November 10, 2023· Wizards of the Coast
The ability that defines The Mycotyrant's power and toughness works in all zones. As long as The Mycotyrant is on the battlefield (and still a Fungus, or somehow a Saproling), that ability will count The Mycotyrant itself.
Card named in this ruling
Fungus
#2November 10, 2023· Wizards of the Coast
If you control a creature that is both a Fungus and a Saproling, it counts only once for The Mycotyrant's middle ability.
Card named in this ruling
Fungus
#3November 10, 2023· Wizards of the Coast
Some cards refer to a player who has "descended this turn." This means that a permanent card has been put into that player's graveyard from anywhere this turn.
No other card is named in this ruling.
#4November 10, 2023· Wizards of the Coast
Some cards refer to the number of times a player descended this turn. Those cards care about the number of permanent cards put into that player's graveyard from anywhere this turn.
No other card is named in this ruling.
#5November 10, 2023· Wizards of the Coast
In either case, it doesn't matter if those cards are still in that player's graveyard.
No other card is named in this ruling.
#6November 10, 2023· Wizards of the Coast
A permanent card is an artifact, battle, creature, enchantment, land, or planeswalker card. Tokens are not cards, and while tokens are put into the graveyard before ceasing to exist, that action doesn't count as a player having descended.
No other card is named in this ruling.
#7November 10, 2023· Wizards of the Coast
Multiple cards have abilities that begin with "At the beginning of your end step, if you descended this turn." These cards don't need to have been under your control at the time you descended. For example, if a permanent card is put into your graveyard during your first main phase and you cast Stalactite Stalker your second main phase, its ability will trigger at the beginning of your end step.
No other card is named in this ruling.
#8November 10, 2023· Wizards of the Coast
Abilities that begin with "At the beginning of your end step, if you descended this turn" will trigger only once during your end step, no matter how many times you descended this turn. However, if you haven't descended this turn as your end step begins, the ability won't trigger at all. It's not possible to put a permanent card into your graveyard during the end step in time to have the ability trigger.
No other card is named in this ruling.