Fleshpulper Giant — ruling 1

If there are no legal targets available, the ability is simply removed from the stack. If you control the only creature with toughness 2 or less, you must choose it as the target, though you can choose to not destroy it.

Fleshpulper Giant — ruling 2

If the target creature’s toughness is greater than 2 when the ability tries to resolve, the ability won’t resolve and the creature won’t be destroyed.

Fleshpulper Giant : règles, fonctionnement et interactions (MTG)

Fleshpulper Giant 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

When this creature enters, you may destroy target creature with toughness 2 or less.

How it works : Fleshpulper Giant

Original English text — Wizards of the Coast / Scryfall

#1July 1, 2013· Wizards of the Coast
If there are no legal targets available, the ability is simply removed from the stack. If you control the only creature with toughness 2 or less, you must choose it as the target, though you can choose to not destroy it.
No other card is named in this ruling.
#2July 1, 2013· Wizards of the Coast
If the target creature’s toughness is greater than 2 when the ability tries to resolve, the ability won’t resolve and the creature won’t be destroyed.
No other card is named in this ruling.