This sound effect is members of a diverse clade of primarily large animals. These include bear deep growl (short only), boar grunt. The sound effect (which was created by Gary Rydstrom and several other sound designers) was made using the roar of an elephant, the growling of a tiger and alligator and the sound of a whale blow (which was used for its breath). A dog attacking a rope toy was used for the sounds of the Bandersnatch tearing a flamingo apart, while cut sequoias crashing to the ground became the sound of the large beast's footsteps. Links: https://www.youtube.com/watch?v=l8nTN_kr4dk