Felix Five-Boots

• WOTC Official Reminder Textofficial rules
  Menace — This creature can't be blocked except by two or more creatures.
• WOTC Official Reminder Textofficial rules
  Ward — Whenever this permanent becomes the target of a spell or ability an opponent controls, counter it unless that player pays [cost].

• WWizards of the Coast2024-04-12
  Official Ruling
  Replacement effects are unaffected by Felix’s last ability. For example, if Charging Tuskodon (“If Charging Tuskodon would deal combat damage to a player, it deals double that damage to that player instead”) deals combat damage to a player, Felix’s ability won’t cause the damage it deals to be doubled an additional time.
• WWizards of the Coast2024-04-12
  Official Ruling
  Triggered abilities use the word “when,” “whenever,” or “at.” They’re often written as “[Trigger condition], [effect].” Some keyword abilities are triggered abilities and will have “when,” “whenever,” or “at the beginning of” in their reminder text.
• WWizards of the Coast2024-04-12
  Official Ruling
  If you somehow control two Felixes, a creature you control dealing combat damage to a player causes abilities of permanents you control to trigger three times. A third Felix causes such abilities to trigger four times, a fourth causes such abilities to trigger five times, and so on.
• WWizards of the Coast2024-04-12
  Official Ruling
  Felix’s last ability affects only triggered abilities whose trigger conditions refer specifically to damage being dealt. It does not affect triggered abilities that would trigger because of the results of that damage. For example, if you control Felix as well as an Ajani’s Pridemate (“Whenever you gain life, put a +1/+1 counter on Ajani’s Pridemate”) and a creature you control with lifelink deals combat damage to a player, the triggered ability of Ajani’s Pridemate will still trigger only once.
• WWizards of the Coast2024-04-12
  Official Ruling
  Felix’s last ability doesn’t copy the triggered ability; it just causes the ability to trigger an additional time. Any choices made as you put the ability onto the stack, such as modes and targets, are made separately for each instance of the ability. Any choices made on resolution, such as whether to put counters on a permanent, are also made individually.

Rulings via Scryfall