Generate a metaphor that describes someone being tired.
"His body felt like a heavy sandbag, dragged along by the exhaustion that weighed him down like an unrelenting force."
Complete the following task based on the instruction and optional input provided.### Instruction:
Generate a metaphor that describes someone being tired.

### Output:
"His body felt like a heavy sandbag, dragged along by the exhaustion that weighed him down like an unrelenting force."