Hydras

[Agent Smith]

What they do is they have multiple "forms" in which the heads are cut off, so, it loses the first 6 hit points, then the hydra switches to its second form with another head gone. With the getting 40 hit points, that's just when it gets left with one head left, that head has more hp than the other heads, the idea being that it is the "great head" so the -34 is just when the hp goes from having a 6 hp form to a 40 hp form. Does that make sense?