These can be a specific type of ability the monster has (Flip, Spirit, Union, Gemini, Tuner, Pendulum), or indicate that the card needs to be Special Summoned in a specific way (Ritual, Fusion, Synchro, Xyz, Link)
It was only available in random packs during a special promotion at the Japan Pokemon Centers for a very limited time and in very limited quantity, in August, 2024
Towards the end I started to run low on time so, sorry again if it got messy
Since these big hitters will likely be the highest HP Pokmon cards in the meta for a while, giving your opponent at least one swipe at them before you get to attack is a fair balancing mechanic that returns from the previous iteration of Mega Evolutions in 2016's XY Pokemon sets
My piece of advice is that whenever you think a card has an interesting effect, pick it up even if there are cards that can do something similar better or even if you dont see immediate use