ததிசி
thathisi
ததீசி.
Na Kadirvelu Pillai Dictionary
    , [tatici]    ''s.'' (''also'' ததீசி.) The name of a   Rishi, who on the application of the gods,  gave his back bone as a weapon to  destroy an Asura, invulnerable to other  weapons, ஒருரிஷி. W. p. 398. 
Miron Winslow