Lizard

A lizard ally is a pet, a forager's lure, or a Find Familiar reskin. The Find Familiar version is the cleanest: a wizard or warlock takes 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 caster's hand. Everything Find Familiar already does, but with Spider Climb for moving 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 its color shifts subtly when certain reagents are nearby. None of this is on the stat block, but the stat block is essentially blank, so you have license to give the lizard a single quiet utility and let the players notice it over three sessions.

In combat the lizard hides. It has 2 HP and AC 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.

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, 2 HP, AC 10, a Bite doing 1 piercing damage on a hit at +2. Spider Climb lets it walk on any surface, including ceilings, without checks. 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 reads 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.

If a lizard somehow ends up in initiative, it flees on its turn. With climb speed equal to walk speed, the lizard goes up the nearest vertical surface, runs the ceiling, and into the smallest crack it can find. If a player attacks it, it dies on a hit. Don't roll. Narrate the motion and move on.

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