The Flash #46

Vixen is calming a jackal by feeding him maternal scent when all of a sudden a pack of dogs and cats rush her and knock her to the ground. It is at this time that Gorilla Grodd appears holding a battered and bruised Wally West by the hair. Vixen replicates Grodd's scent and gains his strength, she loses control and almost kills him, she throws Grodd through a wall where he retreats to his makeshift laboratory. Meanwhile, they take the injured Flash to a safe house to heal. There they concoct a plan to try and defeat Grodd and Wally calls Pied Piper.  
 
Grodd on completion of his Machine gains control of all the animals in Keystone City and sets them on the public. Vixen, uses Grodds scent to find out where he is and they set out to find him only to have Vixen lose control and attack piper AND Wally!Grodd captures the two (Wally and Piper) and locks them up like animals. 
 
The animals Grodd is controling, having gained an equal brain capacity to Grodds start to feel as though they are entitled to some of the power also. This is where we meet "Rex" and the book ends.