The mob I want to create, known as "Bloodghast" (unrelated to a Nether Ghast), is a Vampire Spirit, or in other words, undead. (Burns in daylight, etc) It is hostile to the player, hovers above ground but doesn't actually fly like a Ghast or a Phantom. I would also like it to be able to pass through walls 1 block thick if possible and track players through those walls, but that might be a topic for another thread.
Here is what I have so far:
I included the Blockbench texture and model here to prove that, A: I have both (.png and .java), and B: So you can have an idea what I'm going for. The Bloodghast should be around player's height. In fact, it should be very similar to a Blaze, minus the fireballs and flying part. Any and all help is appreciated.