Grafted Exoskeleton

Equipped creature gets +2/+2 and has infect. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Whenever this Equipment becomes unattached from a permanent, sacrifice that permanent.
Equip {2}

Blade of Selves

Equipped creature has myriad. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Equip {4}

Squall, Gunblade Duelist

First strike
As Squall enters, choose a number.
Whenever one or more creatures attack one of your opponents, if any of those creatures have power or toughness equal to the chosen number, Squall deals damage equal to its power to defending player.