The silliest GX card I've ever seen, that's for sure. Was not expecting this at all, so waking up to the news over here certainly made my morning.
Thinking about the ability, it's nice against energy efficient attackers, like Golisopod / Zoroark / Buzzwole specifically using Jet Punch / Sledgehammer, which I like. Granted, they can put more energy on the card which would nullify the ability, and I used to think that made the card bad to me, but think about it; they're putting more energy on the card, therefore wasting resources just to get past Shuckle's ability. So what if you ran this with energy disruption? Keep it afloat while your opponent attempts to take it down. And as a bonus, it's energy efficient itself so Max Potion and Acerola gotta be viable with this.
Triple poison is fine but it's like Noivern-GX in the case of if only you could do a little bit more damage and this card would be attacking potential. CRI Seviper sounds pretty good to add up the damage but that's a good chunk of my bench space used for this card. I would have higher praise for Wrap GX but theres so much switching cards in this game you gotta use this at exactly the right time.
Incase you couldn't tell, I don't think that this card is too bad. Obviously not at all meta-definining but I could see someone using this card to screw with your opponent hard. It's no Zoroark-GX, but it's no Machamp-GX.