This ancient bug Pokémon was altered by Team Plasma. They upgraded the cannon on its back.
プラズマ団によって 改造された 古代の むしポケモン。背中の 大砲が パワーアップした。
Rulings
Genesect's "ACE Nullifier" Ability only prevents the opponent from playing ACE SPEC cards from their hand. It does not prevent other methods of playing ACE SPEC cards, eg. using Archeops's "Primal Turbo" Ability to attach Legacy Energy from the deck to their Pokémon.[1]
For Genesect's "ACE Nullifier" Ability vs. Jamming Tower: Jamming Tower only shuts down effects of attached Pokémon Tool cards, while the Pokémon Tools themselves are still considered to be attached (the official Japanese FAQ provided an example using Probopass's "Assault Laser" attack[2]). Since the "ACE Nullifier" Ability only checks if there's a Pokémon Tool attached, having Jamming Tower in play does not shut down this Ability even if the Pokémon Tool's effect is shut down.