Separated at Birth

Evil Willow from season six of
Buffy the Vampire Slayer

Ozzy Osbourne

The Wampa from The Empire Strikes Back

The Bumble from Rudolph the Red-Nosed Reindeer

Son of Godzilla

Gary Coleman
(This one was blatantly stolen from http://www.stomptokyo.com)

Lurch
John Kerry
(This one was blatantly stolen from http://www.addamsfamily.com)

Saturn's moon Mimas

Death Star
Thank you NASA

Patrick Swayze
and
Jennifer Grey
and
Jennifer Grey
Derek Jeter
and
Gary Sheffield
and
Gary Sheffield
Nobody puts Jeter in a corner.