Turn Resistance. The topi has advantage on saving throws against any effect that turns undead.
Undead Fortitude. If damage reduces the topi to 0 hit points, it must make a Constitution saving throw with a DC of 5+the damage taken, unless the damage is radiant or from a critical hit. On a success, the topi drops to 1 hit point instead.
Venomous Claws. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit:4 (1d4 + 2) slashing damage plus 2 (1d4) poison damage, and the target must succeed on a DC 11 Constitution saving throw or be poisoned until the end of the target's next turn.
Topis are similar to zombies. Before a topi is animated, its corpse is shrunk until it stands only 2 feet tall, and its heart is cut out and replaced with a leather bag that contains a live poisonous snake. The snake requires neither air nor sustenance, and it magically renders the topi's claws venomous. When a topi dies, the snake inside it dies too. The process of creating a topi is known only to a handful of evil priests and necromancers.