In this riddle you are asked: "What goes in the water black and comes out red?" Which creature or object is being described by this colour change?

Introduction / Context:
This riddle uses a visual transformation to point to a specific sea creature. The phrase "goes in the water black and comes out red" suggests something that changes colour dramatically when it is placed in hot water or cooked. In everyday cooking and food culture, lobsters are famously known for turning bright red when boiled, even though they are dark in colour when alive. Recognising this fact allows you to quickly identify the subject of the riddle.

Given Data / Assumptions:

• The riddle states: "What goes in the water black and comes out red?"
• We must identify the creature or object that fits this description.
• The options include a lobster, an octopus, a crab and a seal.
• We assume the riddle refers to cooking in boiling water, a common real-life situation.

Concept / Approach:
Live lobsters are usually dark coloured, often appearing bluish, greenish or nearly black. When a lobster is boiled in hot water, its shell changes colour to a bright red due to pigments in the shell reacting to heat. This striking change is well known in many cuisines. While some crabs also turn red when cooked, the standard English riddle most famously refers to lobsters. An octopus does not typically go from black to bright red in the same cliché way, and a seal certainly does not.

Step-by-Step Solution:
Step 1: Focus on the clue "goes in the water black." This suggests that the creature is dark coloured before being placed in boiling water. Step 2: Consider the second clue, "comes out red." This indicates a dramatic colour change after being in hot water. Step 3: Recall that lobsters are commonly dark before cooking and bright red after boiling, a detail often mentioned in cookbooks and restaurants. Step 4: Compare this with an octopus, which may change colour in life but is not typically known for a standard black-to-red cooking transformation. Step 5: A crab can also change colour when cooked, but the classic riddle tradition usually names the lobster as the answer, because it is especially famous for turning red. Step 6: A seal does not undergo such a change and is not boiled in water in normal situations. Step 7: Therefore, "a lobster" is the answer that best matches both the colour change and the common riddle convention.

Verification / Alternative check:
To verify, imagine a restaurant tank full of live lobsters. They appear dark and sometimes nearly black under water. After cooking, the lobsters served on plates are bright red and instantly recognisable. This contrast is so iconic that many cartoons and illustrations depict lobsters in red even when alive, reinforcing the association. Checking each alternative option against this vivid real-world process makes it clear that the riddle is pointing to lobsters in particular.

Why Other Options Are Wrong:
An octopus may have various colours and can change shade while alive, but it is not widely known in popular culture for a predictable black-to-red colour shift in boiling water. A crab can indeed turn red when cooked, but the standard and most widely recognised version of this riddle typically uses "lobster" as the answer. A seal is a mammal and not boiled in water in any normal context, so it clearly does not fit the image or the colour transformation described.

Common Pitfalls:
Some learners might overthink the puzzle and consider alternative scientific cases or less common animals. Others may argue for crab because of similar colour changes; however, exam questions and classic riddle collections usually expect the answer that is both scientifically accurate and culturally familiar. In this context, lobster is the safest and most widely accepted choice. When solving riddles, it is useful to choose the answer that best aligns with common knowledge and typical phrasing.

Final Answer:
The creature that goes in the water black and comes out red is A lobster.