Strange cat paralysis?

the cat (moose) is about 9 months old and had 2 kittens about 2 weeks ago. Shes my friends cat, and they found her monday night outside in the garden squirming around and unable to meow. From her hips down she was paralyzed but after the episode she dragged herself off into the woods (presumably to die) but she came home that morning perfectly fine and fed the babies. She had another episode yesterday afternoon when a blue Jay attacked her. they called me over but by the time i got there she had dissappeared again. they plan on taking her to the vet so "take it to the vet" is not helpful here. any theories tho as ot whats going on? shes a terrific mouser..and likes to bring home birds. We thought shed been bit by a snake or got into arsenic but she recovered by morning so i dont think its somethign like that. when they told me about the blue jay i was thinking it could be seizures.... :/