Staining the Shirt with Blood
Scholars have said that staining one's shirt with animal blood has various interpretations; cat's blood might indicate lies from an oppressive ruler, and lamb's blood points to lies from a noble or wealthy man. Generally, blood associated with any animal signifies lies from someone related to that animal or what it represents.
Per Ibn Sirin's Muntakhab al-Kalam fi Tafsir al-Ahlam
Note: These are traditional scholarly interpretations (ijtihad) drawn from a specific classical source — not a binding religious ruling, fortune-telling, or a prediction of the future.