Activated abilities have discrete effects that can be set off when and how you choose, but usually require you to pay a cost first
ORAS has even more Mega Evolution Pokemon than X/Y
It evolves into Zoroark a large and strong Pokemon capable of creating illusions that are indistinguishable from reality
(You could argue Brilliant Stars is the more over-all valuable set, given the number of over $20 cards in there, but even its alt-art Charizard V doesnt quite scrape the $200 mark.) These are, of course, their ungraded prices, with numbers vastly increased if sent of to companies like PSA to receive a grade, especially if they can achieve that all-conquering PSA 10
Final Thoughts: Are They Worth It
Magosi, the Waterveil Magosi, the Waterveil doesnt just bend the rules of turn order, it outright breaks them when built around correctly