Hello!  Right now this deck is in its early stages - I'm not confident that this is the most optimal version of the deck.  I'll let you know what the deck intends to do, and why I've made certain choices.

The intent of the deck is to get into Hydralodon as quickly and as consistently as possible.  Hunter throughout the years has been given an excellent suite of tutor effects that help make somewhat memey or hyperfocused strategies like this one very consistent.  Using Tracking, Selective Breeder, and Harpoon Gun we should be able to find our way into Hydralodon at or before turns 5, 6, or 7.  After playing out your Colossal, you've got Revive Pet as a huge player in the deck - able to recur Hydralodon two times.  Now since Revive Pet is a Discover effect, that means the number of beasts we're able to run - or even summon - is extremely tight.  As far as I understand it, Discover effects look for unique *names* in a given pool of cards, which means that using Revive Pet in a deck with Hydralodon presents the issue that you can only really run/summon *one* beast aside from the Colossal itself, since Hydralodon's Head is also a Beast which will appear in the Revive Pet Pool.  So when casting it, you'll be offered Hydralodon, one of its Heads, and a blank space.  I'm running Rustrot Viper as a tech piece in this slot.  Tradeable means I don't need to have it in my hand when I don't want it, it being a Beast means I can get it with Selective Breeder when I do need it.

Surrounding this main strategy is a fairly weak Secret Shell.  With a lack of access to a lot of Secrets in Standard at the moment, we work with what we've got.  Dun Baldar Bunker and Spring the Trap can thin out our deck and draw us cards, and really the advantage and reactivity that Secrets provide are the main reason we're using this shell at all.