This is Atom Eve.
http://en.wikipedia.org/wiki/Atom_Eve
Simply put, she is a superheroinne who's powers involve manipulating things on the atomic level. She can only affect animal particles under great stress.
(Spoilers ahoy)
In the previous issue of Invincible, she was disembowled with one punch by a Viltrumite called Conquest. Near death and with Invincible's life on the line, she regenerates and releases a major blast, melting Conquest's skin off, giving Invincible enough time to get the upper hand, and deliver the final blow(s).
And these pics take place afterwards, when Invincible is in the hospital.