Suitable First Session Monsters?

I'm having some real trouble settling on an idea for a monster for the first session of my campaign, which I'm supposed to be starting on Monday.

At first I thought about making it an Atmospheric Beast/Energyzoa, with some kind of UFO cult that was feeding people to it as minions. But I couldn't think of how the hunters could actually take something like that down.

Then I thought about making the Monster some sort of faerie creature that was stealing kids and replacing them with changelings. But I know one of my players is planning on making a Monstrous with a Fae background, so I want to maybe save that for when I'm putting together an arc for her character. That also rules out anything else with a Fae origin.

And I don't want to use vampires because they're kinda cliche. Does anyone have any other suggestions of what might make a good Monster for a first session?

I like to kick off with a classic (or even cliched) monster, just to ease everyone into the world. It's a good idea to add something new or unusual, but not too much.

My reasoning is that this lets the hunters (and players) come into the first mystery with a good idea what to expect. Something entirely new means the players have to get up to speed on the creature, which is not what you would expect from experienced monster hunters.

So, with that in mind, here's a short list of things I would consider good first monsters:
- Vampire
- Werewolf
- Ghost
- Demon (or demonic possession)
- Shapeshifter

Alternatively, you could just pick a cool monster from a movie and change it around a little (e.g. like the trolls in "Troll Hunter" but they're reptilian, and their weakness is salt instead of daylight).