Most likely the animal would die. The extreme tempature change, as well as the lack of the animals regular food source, would lead this animal to perish.
What would happen to the animal is that it might die because throughout its whole life it lived in the rainforest. Also because it doesn't know how to live in a desert and it doesn't have the adaptions for the desert.
If anything, the plant or animal might live a bit better off as a grassland receives more rainfall than a desert. There are a number of plants and animals that already live in both the desert and the grasslands.
If a grassland animal moved to the Arctic tundra, you would be following a caribou on its annual migration. You would watch it graze on the grass of the tundra. Then when winter came, you would watch it move south to its winter grazing land. You might also be watching a musk ox which grazes on the tundra year around.An animal without a thick coat would of course freeze to death.
If the desert is located along a coastline it might be subject to a tsunami.
Animals move to other places or they will not survive. Or the population might grow.
Animals move to other places or they will not survive. Or the population might grow.
There are a number of animals that inhabit both deserts as well as rainforests. It would depend upon the particular species of animal. Some would quickly adapt, others might perish.
We may might not be on the same page, but I believe it is El Chupacabra
Desert biomes are normally very dry and hot. There is not much plant or animal diversity in these biomes, although there is some.
you might be infected with rabies
Having traveled extensively in both deserts, I guarantee you will see a lot more fauna and flora in the Sonoran Desert. The Atacama Desert has little plant and animal life.
The Polar bears will die because they are used to living in a colder climate and not a warmer climat.