Magma creams can be obtained by killing Magmas in the nether. Once killing a big or medium Magma, many smaller ones come out and you have to kill them to get Magma Creams. Killing large one also gives you it.
Increase your chances of getting Magma Creams by using a Looting I, II, or III sword!
One of the most annoying things about Magmas that when you kill them, their Magma Creams fall into the lava leaving you nothing for your fighting… man!
Magma Creams are very useful in brewing. They can make Fire Resistance Potions, which are commonly used in the nether and in PvP & PvE.