Missy + Intruder Alarm + Dog Walker + Phyrexian Altar

Missy

Intruder Alarm

Dog Walker

Phyrexian Altar

How it works

1. Activate Phyrexian Altar by sacrificing Dog Walker, adding R/W.
2. When Dog Walker dies, Missy's first ability triggers, returning Dog Walker from your graveyard to the battlefield face down as a 2/2 Cyberman artifact creature.
3. Activate Dog Walker's disguise ability by paying R/WR/W, turning it face up.
4. Dog Walker triggers, creating two 1/1 Dog creature tokens.
5. Activate Phyrexian Altar by sacrificing a Dog, adding R/W.
6. Repeat.

This engine turns a canine rescue into an endless loop by leveraging Missy to continuously recycle Dog Walker from the graveyard as a face-down artifact creature whenever it hits the bin. Phyrexian Altar provides the sacrifice outlet to fuel the disguise cost needed to turn Dog Walker back face up, which in turn triggers its ability to flood the board with two 1/1 white Dog creature tokens. Those extra tokens can be fed right back into Phyrexian Altar to sustain the mana loop, while Intruder Alarm stands ready to untap your creatures upon each new entry to keep the gears turning smoothly.