Sure! Here's a test case generator for the "Deadlock Detection" problem:

```python
import random
import string

def tcgen():
    # Generate a random length for the instruction sequence
    n = random.randint(1, 10000)
    
    # Generate the instruction sequence
    # Ensure the sequence ends with 'u'
    s = ''.join(random.choices('0123456789u', k=n-1)) + 'u'
    
    return n, s

# Generate multiple test cases
def generate_test_cases(num_cases):
    test_cases = []
    for _ in range(num_cases):
        n, s = tcgen()
        test_cases.append((n, s))
    return test_cases

# Example usage:
if __name__ == "__main__":
    num_cases = 5  # Number of test cases you want to generate
    test_cases = generate_test_cases(num_cases)
    
    for n, s in test_cases:
        print(n)
        print(s)
```

### Explanation:

1. **Random Length (`n`):** The length of the instruction sequence `n` is generated randomly between 1 and 10,000.
2. **Instruction Sequence (`s`):** The sequence is generated using `random.choices` to choose from digits `0-9` and `u`. The sequence is ensured to end with `u` by appending 'u' at the end.
3. **Multiple Test Cases:** The `generate_test_cases` function generates multiple test cases by calling `tcgen()` multiple times.
4. **Example Usage:** The example usage generates 5 test cases and prints them.

This will help you generate a variety of test cases that can be used to thoroughly test the deadlock detection logic.