Cockatrice have a special stat-draining attack, which they use if the player is not wearing protective equipment. It will shoot out beams from its eyes, quickly reducing combat stats (including agility) to dangerously low levels (1/4 of the player's original levels, e.g. 15/60) and causes rapid damage for up to 110 life points per hit (it does more damage with higher levels). These beams always hit a fixed amount. This is why a mirror shield is necessary.
If the player is protected, however, they fight using standard melee and ranged attacks. They have few life points and do not hit substantially. Their attack speed is the same as a scimitar or mace. They are weak against crush attacks, although any melee weapon will suffice.
^Jagex. Mod Timbo's Twitter account. 19 January 2018. (Archived from the original on 22 January 2019.) Mod Timbo: "1/1280 if you hit the RDT, requires T4 luck to be worn in order to get a hold of it. Of course there are tons of different ways to access the RDT so it changes massively depending on what you're fighting, what you're wearing etc."