The 61-year-old was seen striking Ms Jayalalithaa's grave at least thrice while muttering something in apparent anger. By all available accounts, she took a "mighty vow". Or three. An AIADMK tweet said she pledged to "overcome hurdles, treachery and plots against her".
The Hindu claims that Ms Sasikala enacted an ancient Tamil ritual for revenge - Vanjinam Uraithal - apparently for battlefields where oaths were taken to avenge the death of a king or a soldier. It is still followed in villages, said the report.
Now, videos, GIFs and pictures are circulating all over Twitter. Many used humour to try and interpret what Ms Sasikala did.
Tweeple, who live for such moments, immediately began posting versions of the clip - some imagined Ms Sasikala as a WWE contestant and others suggested the reaction came after she spotted a mosquito on the memorial.
What actually happened! pic.twitter.com/PjE71Mwskf- Madurai Fellow (@rajivrajaram) February 15, 2017
Tu toh ghotala karke margai jail muje ho rahi h.pic.twitter.com/tOomCFAbp4- unMask (@Mr_LoLwa) February 15, 2017
Sasikala's triple hand slam on the grave reminded me the WWE referees, slapping the mat 3 times when a wrestler defeats the other.- Princestructor (@revprince) February 16, 2017
V. Arasu, former head of the department of Tamil, Madras University told The Hindu: "They would slam the ground as they treat it as Mother Earth. Mr. Panneerselvam observed a vow of silence at the memorial; Ms Sasikala has taken a different kind of vow."
Ms Sasikala, a former video store owner, lived with Ms Jayalalithaa for nearly three decades and performed her last rites after she died on December 5.