Depending on how you look at it, Companion could be ludicrously powerful (having this much control over every opening hand is crazy strong) or overly restrictive (many of these conditions seem onerous, especially for Standard)
She thrives in games that go long, where her consistent life drain becomes a clock that opponents simply cant ignore
Gimmicky, and in larger formats with multiple players and much more things to track of, a logistical nightmare
Weakness: [Electric] x2 Resistance: [Fighting] -20 Retreat Cost:
Whenever equipped creature deals combat damage to a player, put a +1/+1 counter on a creature you control, then proliferate
Notably, this means that you may discard a card to keep Argentum Masticore on the battlefield even if there isn't a legal target for that second triggered ability