A very common problem with toddlers and sometimes in children of all age groups is Temper Tantrums. Temper Tantrums are commonly seen when the kid is mentally disturbed and can manifest as uncontrolled anger, spells of breath holding, teeth biting / grinding, protraction, etc. This can be a brief phenomenon to attract attention or due to a deeper psychological issue.
They could sometimes be mistaken for fits / seizures and could raise a panic in the household. When ever in doubt, remember that actions during seizures are involuntary and the person behaves against his will and has no control of his movements, whereas in Temper Tantrums, the kid is intentionally unresponsive and appears stubborn in contrast to lack of control in seizures. Unresponsive behavior can sometimes mimic absence seizures but we can differentiate on the basis of the general mood of the child when such events occur.
Temper Tantrums are also seen as part of sibling rivalry to attract attention from parents.
This could be a passing issue and many toddlers learn other positive ways to attract attention from parents. If this continues to be an issue with your kid, its best to consult a child psychologist for guidance.