Target 1 face-up monster on the field; its ATK and DEF become half its current ATK and DEF until the end of this turn. Once per Chain, when a Trap Card is activated while this card is in your Graveyard: Special Summon this card as a Normal Monster (Aqua-Type/WATER/Level 2/ATK 1200/DEF 0). (This card is NOT treated as a Trap Card.) If Summoned this way, this card is unaffected by monster effects, also banish it when it leaves the field.
Since Paleozoic Hallucigenia, as a monster, is summoned at such a low level, Amulet of Ambition is a great card to use for a powerful attack boost.
Here are some other Paleozoic monsters you could use as they are all able to trigger each other's special summon effect. Paleozoic Pikaia and Paleozoic Marella is a great way to send Your Paleozoic monsters to the graveyard. Paleozoic Leanchiolia can return banish Paleozoics to your graveyard.
This card is buggy, the effects doesn't activate properly some of the time as my opponent uses it on me and my monsters don't lose half their attack, when i do it, they don't lose half either, neither of us had effects that countered it, Konami needs to get it to work!