Ravager

Ravagers or illager beasts are large hostile mobs that spawn in raids.

Raids
Ravagers can spawn starting at wave 2 as part of raids.

Behavior
Ravagers (formerly Illager Beasts) are hostile towards players, iron golems, and villagers within a 16-block radius. They attack by ramming enemies with their head, dealing damage and high knockback. They will also destroy crops and leaves that they run quickly into, though flowers, saplings, and crops such as melon and pumpkin stems are unaffected.

If blocked by a shield while attacking, no damage occurs and knockback is halved. The ravager has about a 50% chance to become stunned and unable to move or attack for around 2 seconds. After this period, it will emit a roar that does damage and high knockback (which increases with proximity) to nearby entities. The roar can knock back nearby Illagers. In spite, the beast does not attack pillagers when they shoot the crossbow arrows at it.

Even though they are heavy, they can swim. Their apparent weight gives them 50% chance of 100% knockback resistance.

Drops
Upon death, ravagers drop 0–1 s.

Trivia

 * "Ravager" and "Behemoth" were listed as alternate name suggestions for the illager beast. In 19w05a, illager beasts were renamed to ravagers.