This Pokémon can use the attacks of any Pokémon-GX or Pokémon-EX on your Bench or in your discard pile. (You still need the necessary Energy to use each attack.)
Attacks
200Miraculous Duo-GX
If this Pokémon has at least 1 extra Energy attached to it (in addition to this attack's cost), heal all damage from all of your Pokémon. (You can't use more than 1 GX attack in a game.)
How much is Mewtwo & Mew-GX #71/236 worth?
Mewtwo & Mew-GX #71/236 is a Rare Holo GX card from Unified Minds (2019) — today it trades at roughly $147.74 ungraded.
Grading changes the math on this one: a PSA 10 is valued around $725.00, roughly 4.9x the raw price, while a PSA 9 sits near $150.00. 6,109 copies have been graded to date, and 42% of them came back a 10 — worth knowing before you pay grading fees.
These figures come from nightly market-data syncs verified against completed sales. Use the chart above to see the trend before you buy or sell.