Step 1: Note the key words.
The body we want is small, rocky and irregular in shape, orbiting the Sun.
Step 2: Test comets.
Comets are made mostly of ice and dust and grow a glowing tail near the Sun, so they do not fit the rocky description.
Step 3: Test stars.
Stars are huge balls of hot glowing gas, not small rocky lumps, so they are out.
Step 4: Discard the odd option.
Aliens are not a type of Solar System object at all, so we ignore that choice.
Step 5: Identify the right body.
Asteroids are small rocky and metallic objects with irregular shapes, mostly found between Mars and Jupiter.
Step 6: State the answer.
Therefore the small rocky, irregular bodies are called asteroids.
\[ \boxed{\text{Asteroids}} \]