What creature goes through a period where it gains 10 pounds an hour?

The creature that gains 10 pounds an hour is the blowfish (or pufferfish). When threatened, this fish can inflate its body by taking in water or air, causing it to swell significantly in size. This dramatic change can occur rapidly, making it appear as if it has gained a substantial amount of weight in a very short period. However, this is a temporary defense mechanism and not a typical weight gain scenario.