The humpback spotted splashing in the East River earlier this week has seemingly left the busy channel as quickly as it came — but not without leaving a whale-sized mark on the Big Apple. The US Coast Guard issued a stark warning for boaters to pull back their speeds and leave the cetacean alone,

A whale was spotted in the East River on Monday near the Brooklyn and Manhattan bridges, flashing its tail out of the water just close enough for people on the Brooklyn shore to get a peek, according to the U.S. Coast Guard, which received multiple reports of the underwater mammal.

People on the Brooklyn shore got a glimpse of the whale flashing its tail out of the water, according to the U.S. Coast Guard, which received multiple reports from spectators