"Quick, Rhirhok—teach me to swim!"
—Makht, goblin casualty

Floodgate

Defender
When this creature has flying, sacrifice it.
When this creature leaves the battlefield, it deals damage to each nonblue creature without flying equal to half the number of Islands you control, rounded down.

Dominaria Remastered

Defender
When Floodgate has flying, sacrifice it.
When Floodgate leaves the battlefield, it deals damage to each nonblue creature without flying equal to half the number of Islands you control, rounded down.

The List

Mirage

If Floodgate gains flying, bury it.
If Floodgate leaves play, it deals to each nonblue creature without flying 1 damage for each two islands you control.

Floodgate’s first triggered ability is a state trigger. It won’t trigger again while the ability is on the stack, but if the ability is countered and Floodgate still has flying, it will trigger again immediately.