Read the text up.
Deathstalker: add 2 poison damage for each successful attack.
Forest Scorpion: add 1 poison damage for each successful attack.
Dune Scorpion: add 1 poison damage for each successful attack, 1 extra damage for each card played.
Chrysaora: inflict 1 poison damage at the end of every turn.
Toadfish: inflict 1 damage per turn to a target creature.
Parasite: inflict 1 damage per turn to a target creature.
Poison damage = damage done to player. Is player-specific.
Antimatter = add a damage multiplier of -1 permanently. The attack will always be successful.
Creature attacking creature is not counted as successful attack (to player). Hence no poison damage.
Creature dealing negative damage is counted as successful attack, triggering the effect. AM only inverts the damage, the effect still stands. You don't expect a AM'd Mind Flayer loboing a creature gives random ability instead, or AM'd Lava Golem to shrink (-2 | -2) instead.
While thematics are good, the most important thing in game is mechanics. Else, someone would start complaining about why would a golem, a mineral creature, be able to produce firefly or scarab. Or why would a Bone Dragon not turn into a random dragon when targeted by RT. Or why can't a Cockatrice stun a creature.
The mechanic of scorpion's attack and effect are separate. Scorpion effect could currently only trigger against opponent's HP, not creature's. And it will trigger if the scorpion managed to touch the opponent.
This is a nice change indeed, but i will not support AM making scorpion giving purify counter (not yet suggested. Just in case you want to argue that, read my post again.)
