Yup, it's an ability called "Find Familiar: Scratch" You need to have had a few interactions with him in the camp before the ability appears. I think it can be found in the "Common" section of your spellbook once you have it.

You also don't need to worry about him dying. You can always resummon him. But he is fairly useless in combat and other familiars are better.

You can also summon the owlbear cub, Mayrina's husband Connor, Us the brain creature from the nautiloid, 4 ghouls from the Necronomicon of Thay, a fairy from the broken moonlantern, the quasit Shovel. I think that's all of them.

You can just summon him again though? I've had scratch die, but he can still be resummoned.