Your Dexterity score increases by 2, and your Constitution score increases by 1.

Pseudodragons, being cousins of true dragons, share their long life. They mature at the age of 5 and can live for 160 years

Most pseudodragons are pleasant in demeanor, commonly being neutral leaning towards good. Extreme and evil alignments are incredibly rare, but not unheard of.

Pseudodragons are the size and weight of a large house cat, though with their tail they are closer to 3 feet long, and possess a similar wingspan. Your size is Tiny. As a tiny creature, you interact with the world differently then your larger peers and have the following rules: You take up a space of 1' cube; you may move through the space of size medium or larger creatures, and vice versa, though this movement is still counted as difficult terrain. You eat and drink much less than other beings, so rations last you twice as long. You have advantage on climbing checks, but disadvantage on all other strength checks while this size. You cannot wield Heavy weapons, Shields, or Two-Handed weapons unless it is made specifically for your size. Normal armor does not fit you and must be made specifically for you. Attack rolls are at disadvantage unless using a weapon with the Light or Finesse property or the item is specifically built for you.

Your base walking speed is 15ft and you have a fly speed of 50ft. Due to your Deepcrawler variant you also have a burrowing speed of 10ft.

You have draconic ancestry. Choose one type of dragon from the Draconic Ancestry table. Your damage resistance is determined by the dragon type, as shown in the table.

Draconic Ancestry

Once per short rest, you can choose to coat your fangs, tail or a melee weapon in venom that lasts for 1d4 successful attacks. Alternatively you can coat 1d4 arrows or bolts. As a Deepcrawler Psedodragon your venom acts as a paralysing agent and requires a successful hit to have effect. On a DC13 saving throw, the target suffers the venoms effect for 1d4 rounds. The venom loses its potency after one minute.

You have resistance to the damage type associated with your draconic ancestry.

You can speak, read, and write Draconic. Draconic is thought to be one of the oldest languages and is often used in the study of magic. The language sounds harsh to most other creatures and includes numerous hard consonants and sibilants.