-LRB- The talent pool for this one includes the directors of `` Shrek 2 '' and `` Shark Tale '' and the writers of `` Kung Fu Panda '' and `` The Rocker , '' incidentally . -RRB- High concepts , top-notch voice talent and scattershot pop cultural references are no compensation for a coherent script . The XXXL lady in question -- dubbed `` Ginormica '' by her U.S. military guards -- starts out plain and petite Susan Murphy -LRB- voiced by Reese Witherspoon -RRB- , until a meteorite hits her just minutes before she 's supposed to tie the knot with unctuous chauvinist Derek -LRB- Paul Rudd -RRB- . Her rapid growth spurt saves her from that particular fate worse than death , even if at first glance her new roommates do n't look like much of an improvement . There 's Dr. Cockroach -LRB- Hugh Laurie -RRB- , a mad scientist who semi-advertently mutated with a bug ; B.O.B. -LRB- Seth Rogen -RRB- an amorphous blue jelly-like blob who gets on just fine without a brain ; Missing Link -LRB- Will Arnett -RRB- , a gung-ho amphibian who 's all mouth ; and a giant dust mite
-LRB- CNN -RRB- -- Watch out ! Lock up your loved ones ! Another bloated , over-produced , high-concept monstrosity has escaped from the labs at Dreamworks Animation , and it 's out to devour your kids . Susan , aka `` Ginormica , '' has to save the world in `` Monsters vs. Aliens . '' But do n't be too alarmed . `` Monsters vs. Aliens '' is relatively harmless -- a toothless satire with a knee-jerk feminist theme and a sorry excuse for a plot . That sounds harsh , I know . Who does n't want to see a 50-foot woman careening through San Francisco on skates that turn out to be automobiles -- the ultimate demolition roller derby ? But think about that , just for a second . Roller skates work because they have fixed wheels . Try it with motorcars and you wo n't get very far . Is that too picky ? Perhaps , but you would n't find Pixar playing so fast and loose with the laws of physics , and that kind of inattention to detail is typical of the lackadaisical storytelling here and in other Dreamworks animated features .