Shield Dancer — ruling 1

If the ability is used twice, it will cause the next two attacks this turn (which only happens if something gives a player two attacks) from the creature to “reflect” back to itself. It will not result in double damage back from a single attack.

Shield Dancer : règles, fonctionnement et interactions (MTG)

Shield Dancer 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

: The next time target attacking creature would deal combat damage to this creature this turn, that creature deals that damage to itself instead.

How it works : Shield Dancer

Original English text — Wizards of the Coast / Scryfall

#1October 4, 2004· Wizards of the Coast
If the ability is used twice, it will cause the next two attacks this turn (which only happens if something gives a player two attacks) from the creature to “reflect” back to itself. It will not result in double damage back from a single attack.
No other card is named in this ruling.