Lizard

A lizard ally is a pet, a forager's lure, or a Find Familiar reskin. The Find Familiar version is the cleanest tactical answer: a wizard or warlock with the Pact of the Chain or Find Familiar spell can take a lizard form for the same Tiny size, 2 HP, and Darkvision 30 ft. The lizard familiar offers Help on attacks against creatures within 5 feet, scouts through gaps the party can't squeeze through, and delivers touch spells from the wizard's hand. Everything Find Familiar already does, but with a 20 ft. climb speed that lets it run the inside of a chimney while the bandits search the room.

As a non-magical companion the lizard is a child's pet or a botanist's living tool. The druid's apprentice keeps a lizard on her shoulder because it eats the gnats that swarm at dusk. The alchemist keeps one because it changes color subtly when certain reagents are nearby. None of this is on the stat block, but the stat block is essentially blank, so the GM has license to give the lizard a single quiet utility hook and let the players notice it over three sessions.

In combat the lizard hides. It has 2 HP and an AC of 10, so a stiff breeze kills it. The familiar version takes the Help action and otherwise stays out of range. The pet version climbs to a high shelf and waits the fight out. If a hostile spell catches the lizard's owner, the lizard dies in the splash, and the table will care about that more than they expected.

Don't roll for the lizard. Narrate it, the same way you narrate the campfire or the smell of rain. It is a recurring sensory detail, not a combatant.

A lizard is a CR 0 prop. Tiny size, 2 HP, AC 10, no traits, no actions, 20 ft. walk and 20 ft. climb. There is nothing to fight here, which is the entire point of having a lizard in your prep file. The lizard is the texture of a place. It scuttles across the temple wall while the cleric is reading the inscription. It darts under the door when the rogue picks the lock. It is on the windowsill when the wizard wakes up.

Use lizards as scene-setters in environments that should feel alive and slightly unfamiliar. Sun-baked ruins, swamp boardwalks, jungle altars, the back rooms of a Calimshani souk. Drop one or two in the box text, never roll for them, and let the players decide whether to pay attention. A player who tries to catch a lizard rolls a Dexterity check against a passive 10 and gets a story about being the kind of person who catches lizards. That is the whole encounter.

If a lizard somehow ends up in initiative, the answer is almost always that it flees on its turn. Climb speed equals walk speed, so the lizard goes up the nearest vertical surface and into the smallest crack it can find. If a player attacks it for some reason, it dies on a hit. Don't roll for it. Narrate the wet sound and move on.

The one tactical use is as a distraction prop. A spellcaster who casts Find Familiar with a lizard form gets the same statblock and a body that doesn't look like a familiar to enemies who don't know the spell. Outside that case, the lizard's value is atmosphere.

Have the lizard cock its head at the rogue while she is rifling the priest's desk. Players catch eye contact with prey animals at the strangest moments and remember it.