Let's break down the clues one by one to solve the puzzle:

 

1. **The child who is dressed as the monster has collected 20 sweets.**  

   → The monster collected 20 sweets.

 

2. **Danny is not wearing a witch costume.**  

   → Danny is not the witch.

 

3. **Jodie has collected the least sweets of the four children.**  

   → Jodie collected the fewest sweets (15).

 

4. **The child dressed as the spooky ghost has collected five more sweets than the monster.**  

   → The ghost collected 25 sweets (because the monster has 20 sweets, and the ghost has 5 more).

 

5. **Seb’s goody bag contains 20 sweets.**  

   → Seb is the monster (since the monster has 20 sweets).

 

6. **Natasha is the child wearing the orange pumpkin costume.**  

   → Natasha is dressed as the pumpkin.

 

7. **The monster costume is not worn by Jodie or Danny.**  

   → Since Seb is the monster, Jodie and Danny are not.

 

8. **Natasha has collected five more sweets than the child dressed as the ghost! Natasha is not the witch!**  

   → Natasha (pumpkin) collected 30 sweets. The ghost collected 25 sweets. Natasha is not the witch.

 

### Filling in the table:

 

- **Seb** is the monster and collected **20 sweets**.

- **Jodie** collected the least sweets, which is **15**, and since Natasha is the pumpkin, Jodie must be the **witch**.

- **Natasha** is the **pumpkin** and collected **30 sweets**.

- **Danny** must be the **ghost** (the only remaining costume) and collected **25 sweets**.

 

### Final Answers:

 

| Child | Number of sweets | Costume |

|---------|------------------|----------|

| Jodie | 15 | Witch |

| Danny | 25 | Ghost |

| Seb | 20 | Monster |

| Natasha | 30 | Pumpkin |