Myr Welder

When this creature dies, you may draw a card.

As an additional cost to cast this spell, sacrifice a creature. Draw three cards.

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.) Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Target creature gets +1/+1 and gains trample until end of turn.

Enchant creature Enchanted creature has infect. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Defender Metalcraft — As long as you control three or more artifacts, this creature gets +2/+2 and can attack as though it didn't have defender.

Flying At the beginning of your upkeep, if you control no Thopters other than this creature, return this creature to its owner's hand and create five 1/1 colorless Thopter artifact creature tokens with flying.

At the beginning of your upkeep, you may put a charge counter on target artifact.