June 10, 2011 -- Heidi, the cross-eyed opossum we first told you about in January, made her media debut at the Leipzig Zoo. In three weeks, Heidi will be appearing before the public alongside some 300 other animals and 17,000 plants in a new tropical enclosure.
Although Heidi's condition is certainly unusual, this opossum has it easy compared with other truly bizarre animals.
Explore some unusual creatures in this slide show and find out just how wild the animal kingdom can get.
A snake, found in Suining in China’s Sichuan province, apparently grew a foot out of its body.
The foot is roughly two centimeters (less than one inch) long and has four claws.
The snake was discovered by Duan Qiongxiu, 66, who awoke in the middle of the night startled to find the creature in her home.
Duan was so terrified that she beat the snake to death. However, she has preserved the specimen, attracting many visitors to her home.
A two-faced, four-eyed calf is given milk from a farmer at a cattle stable in China's Gansu province.
Because of the size of the calf, it had to be born by Cesarean.
This two-headed turtle hatchling was spotted in Ostional, Costa Rica, in 2005.
The specimen was an Olive Ridley turtle, a species which arrives en masse to lay their eggs in Ostional.
The turtle appeared to be healthy and the cause of the deformity is unknown. Some environmental experts suspected that toxic contamination from agricultural and industrial waste may have played a role.
Although it may appear as though two fish are engaged in some kind of synchronized swim, in fact, these two conjoined Nile Tilapia fish share the same body.
The bigger fish tends to protect the smaller one from harm while the smaller one looks for food at the bottom of the aquarium.
Snakes apparently can not only grow extra limbs, but also an extra head.
This albino rat snake was featured as part of an exhibit of two-headed animals at the World Aquarium in St. Louis, Mo.
The snake's long lifespan stunned scientists. Most snakes with this deformity die within two weeks after being born. In 2007, the snake died at 8 years old.
In 2007, a piglet in Xi'an, Shaanxi Province, China was born with two mouths, two noses and three eyes.
Incidentally, 2007 was the year of the pig in Chinese zodiac, a sign of fertility and virility.
The extra legs on this leopard frog sure aren't an evolutionary enhancement to improve this amphibian's vertical leap. In fact, the two extra deformed hind legs are by an infection of a type of parasitic worm.
Chemical byproducts from farming and ranching ends up in groundwater, triggering a chain of events that causes these deformities in frogs.
Unlike other animals who developed their distinct features naturally, this two-headed dog is actually the creation of Soviet surgeon Vladimir Demikhov, who grafted the head and front legs of a puppy onto a German shepard.
Although this bizarre experiment could certainly be considered an act of cruelty, Demikhov's work relating to organ transplants set the stage for similar operations on humans in the future, according to the New York Times.