From reddit:
The Hit Points are the Gum's Health, which is Tall-nut level. Gum Health Boost is the health of the zombie that's gummed, multiplied by a percentage, and added to the health of the Gum. So at lvl1 it's 300; that means that the top health of the zombie that's gummed is multiplied by 300% and added. At level 10 it's multiplied by 1000% (10x).
The gum takes smash damage, but if it's a gargantuar's gum, it's basically smashing through its own health times at least 3.
All-stars... they do smashing damage but no insta-kill. So how many smashes can gum take? It depends on the health of the zombie that's gummed.
The arcade machine will just crush a Gumnut that hasn't gone off. But if a Gumnut has gummed another zombie, the Arcade zombie will push the cabinet past the gummed zombie, and then will be blocked by the gummed zombie and start doing chewing damage on the gum. [Haem's comment: It's likely the same story with Ice Blocks though that wasn't specifically addressed in the reply]
This means that the gum depends on the zombie's health. So, although, the Zombies in Arena do more damage, they also have more health which makes the gum tougher. It's a really interesting plant.
The Football helmets do damage with there pushing effect, so they will "eat through" the gum. It's just takes a long time 🙂