Nasty Little Rabbit

Paying 2 life during your first main phase makes Desolation Prowler a 4/4 until end of turn, enabling the Rabbit's beginning-of-combat trigger as early as turn three.

Galion continuously enables the Rabbit's Ferocious trigger. Its accumulated +1/+1 counters remain effective after Galion makes it base 4/4, so it attacks as a 4/4 plus all of those counters.

Head of the Hunt naturally has 4 power, reliably turning on the Rabbit while also adding Wolf tokens that help stabilize the battlefield.

Its 5 power immediately enables Ferocious, and its recurring Wolf tokens help protect both creatures so the Rabbit can keep growing over multiple combats.

Putting multiple +1/+1 counters on the Rabbit can raise it to 4 power, allowing it to satisfy its own Ferocious condition and continue growing each combat even without another large creature.

Keeping the Spider on the battlefield enables the Rabbit to gain a +1/+1 counter at the beginning of each of your combat steps, turning a cheap creature into a scaling threat.

Ordinary Bear is an on-color, durable 4-power creature that reliably turns on the Rabbit's recurring +1/+1 counter trigger.

Hospitality can permanently raise a 3-power creature to the 4-power Ferocious threshold, enabling Nasty Little Rabbit to begin gaining its own +1/+1 counters each combat.

Great Ugly-Looking Goblin's 4 power turns on Nasty Little Rabbit's Ferocious trigger, which repeatedly gives the Rabbit +1/+1 counters; the Goblin's static ability then gives the growing Rabbit menace.

Mirkwood Pathmaker naturally reaches 4 power at four lands, reliably enabling the Rabbit's Ferocious trigger so it gains a +1/+1 counter each combat.

Till and Tend accelerates the deck toward Beorn, whose 5 power then reliably enables the Rabbit's Ferocious trigger every combat.

Large Bear's 5 power immediately enables Ferocious, while its haste creates pressure the same turn the Rabbit begins growing.

Its landfall trigger can place two counters on the Rabbit at a time; two triggers make the Rabbit large enough to satisfy its own Ferocious condition and continue growing without another enabler.

Once Ferocious is enabled, Nasty Little Rabbit grows at the beginning of combat and Wilderland Scrounger adds another counter when it attacks, allowing the cheap Rabbit to scale quickly while both cards use the same 4-power enabler.

Beorn automatically satisfies the Rabbit's Ferocious condition, so it receives a +1/+1 counter at each combat; Beorn can also turn it into a Bear to give it an additional +2/+2 and advance the draw threshold.

Misty Mountains Raider naturally satisfies Nasty Little Rabbit's ferocious requirement with its 4 power, allowing the Rabbit to gain a +1/+1 counter at the beginning of each of your combats while the Raider remains in play.

A landfall trigger makes the Meditator a 4/2 until end of turn, turning on the Rabbit's beginning-of-combat Ferocious trigger for that turn.

Crewing Great Gilded Boat before the beginning-of-combat trigger makes it a 4-power creature, enabling Nasty Little Rabbit to receive its recurring +1/+1 counter.