The Frost is shaped like a snowflake and is a mob that is small, it floats (like a Blaze except smaller) and is only dangerous in some situations. When it cannot get close enough to do a melee attack it will shoot fireballs, like Ghasts. The fireballs will most likely hit trees and will burn them down with all around them so it isn't recommended to make any houses at all in the Taiga Biome.
The Glacon will easily destroy you even if you have fully enchanted Realmite Armor in 3-4 hits. The only good thing about this mob is that you can beat it with an enchanted Bloodgem Sword or any better sword. The Glacon is recommended to be avoided because it has terrible drops compared to the Frost. The Glacon only drops a few Frozen Shards while the Frost drops multiple Frozen Shards, Ice Stones and Tomatoes. Frosts also have less health than Glacons do.
While starting off, stay out of this deadly biome and later on, only enter this biome with caution. But if you have great armor, then this biome will just be another fun adventure for you with these two mobs.