This was a big animal! So when the my boss came to me suggesting the client wanted the mastodon in a block of ice we were stumped as to how would a block of ice that large have formed. An ice cube would not do, where would a fridge that large get the power required to freeze something that large. Then we tried icebergs, thinking that maybe the tails of 90 percent of the iceberg is under the surface. That should be easy, but there are no stock photos of the underside of icebergs. The lighting is terrible. and with the water not helping with light refraction it is no surprise that there are not stock photo agencies devoted to the subject. Also we noted that iceberg ice is not really see-through and thus the concept would be affected.
After trying about 9 different types of ice cubes, icebergs (illustrated and photographic) I combined a whole bunch of each and created my own block.