The word is splendid.
Amazing
Astonishing.
A phenomenon is something extraordinary that happens or an amazing person. 'Phenomenal' is therefore the adjective that describes the person or event. 'Good' simply does not live up to the description.
Another word for strange event or equation
awesome
The word is splendid.
fanominal
wow
happenAlso occur or two words ...will be
thrilling, breathtaking, amazing
an amazing vacation
marvellous
Amazing
Astonishing.
Awesome
Event