Slime and Magma Cream on anvils to make them bounce or do other things.

Anvils should bounce on slime blocks but also you should be able to coat them in slime so you can drop them and they bounce taking less damage than normal, they would look covered in the normal minecraft green slime near the bottom and have a slightly visible trail of slime while flying through the air.. 

However using magma cream should turn them into meteors, dropping them should make them cause explosions based on fall strength, with a maximum being like 1.5x normal tnt however they should also cause fire(MAGMA cream) and of course leave a fire streak in the air.