Taken from the Vine:
Monica has the ability to change into any aspect of the electromagnetic spectrum. She can turn into photons (light), electricity, microwaves, radio waves, gamma rays cosmic rays, X-rays, ultraviolet radiation, electricity, infrared radiation and neutrinos, or any known form of energy from the electromagnetic spectrum; by focusing her light-energy form into a tight beam, she can become a laser. She can travel at speeds up to and including the speed of light, depending on the type of energy she converts into. She is invisible and intangible in many of her energy forms.
Monica also has the ability to fire off blasts of whatever energy she becomes. She can also project these energies from her body while she is in human form, usually in the form of energy blasts from her hands; a variation of this ability enables her to project light-based holographic illusions. When she encounters a new or unfamiliar energy, Monica can often duplicate it given enough time for analysis as well as absorbing energy from outside sources, such as when she replicated and drained the verdant will-powered energies of an extra-dimensional emerald gladiator. She was even capable of absorbing and manipulating the energies of Kyle Rayner's Green Lantern ring as seen in the Avengers/JLA crossover storyline by matching the energy's specific wavelength.
Monica tends to be physically insubstantial in her energy forms, though with concentration and effort she can sometimes perform tasks such as briefly grasping an object, either by partially solidifying or by applying some sort of force to the object in question.
For a short time while recovering from life-threatening injuries, Monica seemed to lose her electromagnetic abilities, but then developed new abilities based on the shunting of inertia and weight into the dimension where Monica formerly drew electromagnetic energy from (as theorized by the Fantastic Four's Reed Richards). This new power manifested as a full-body energy field that was actually an event horizon between Earth's dimension and the source dimension. She could use the field to generate force upon impact (including charging into or punching an opponent) and to carry heavy loads (by shunting much of the weight out of Earth's dimension), thus simulating superhuman strength. She could also fly by "riding" the energy field, though at much slower speeds than she could as an electromagnetic being. The field provided Monica with a measure of protection from attack, within limits; she would still feel a fraction of any impact, and a sufficiently powerful attack could still do her serious injury. Eventually, however, her original powers re-emerged