Unsettled Mariner
Creature — Shapeshifter
Changeling (This card is every creature type.)
Whenever you or a permanent you control becomes the target of a spell or ability an opponent controls, counter that spell or ability unless its controller pays 
.
The call of the sea shapes many souls.
John Stanko
Modern Horizons (MH1)
• #216Rulings
If you and a permanent you control each become the targets of the same spell or ability an opponent controls, Unsettled Mariner’s ability will trigger twice. The same is true if two permanents you control each become the targets of the same spell or ability an opponent controls.
(wotc • 2019-06-14)
If a spell or ability an opponent controls targets only you or only one permanent you control, but it targets you or that permanent multiple times, Unsettled Mariner’s ability triggers only once.
(wotc • 2019-06-14)
Rulings
If you and a permanent you control each become the targets of the same spell or ability an opponent controls, Unsettled Mariner’s ability will trigger twice. The same is true if two permanents you control each become the targets of the same spell or ability an opponent controls.
(wotc • 2019-06-14)
If a spell or ability an opponent controls targets only you or only one permanent you control, but it targets you or that permanent multiple times, Unsettled Mariner’s ability triggers only once.
(wotc • 2019-06-14)