- For information on the character, see Isaac.
Phase 1 Edit
Isaac will appear lying down in the center of the room, crying on the floor. He shoots 12 high-velocity tears in a radial burst, and will retaliate with streams of tears when hit.
Phase 2 Edit
At three quarters of health, a light will shine on Isaac, and he jumps from the ground. Isaac will then start shooting 4 large purple tears, which home slightly, in all directions. He will still retaliate with some tears when hit.
Phase 3 Edit
Triggered near one quarter of health. Isaac will grow angel wings, and start floating. White beams will be randomly be shot down from the sky (Similar to Crack The Sky and White Pony), Angel Babies will start spawning, and the same homing projectiles from before will be shot in six directions at the same time (similar to shots dispersed from killing Red Boom Flies). At this point, Isaac will no longer retaliate with tears when hit.
- Using The Bible during the fight will kill the player instantly even after defeating Isaac, (unlike the bosses Mom, Mom's Heart, or It Lives, which kills those bosses instantly, and will kill the player instantly like the bosses Satan and ???) unless the player has The Wafer item.
- Using The Book Of Belial, or The Devil/The Empress Tarot Cards during this fight sets Isaac into a frenzy, increasing his attack speed by several times.
- If the player uses The Hourglass, Isaac will fire blood tears instead of the usual blue tears and purple homing tears.
- The third form is referenced in the DLCs trailer, which showed Isaac sprouting wings.
- When in Phase 1, Isaac makes the same weeping noises as the Mulligan.
- When Isaac was first added in the initial release of Wrath of the Lamb, his third form only consisted of the rays of light, except with a tremendous rate of firing.
|Basement||Larry Jr. • Monstro • The Duke of Flies • Gemini • Steven • Famine|
|Cellar||Widow • Pin • The Duke of Flies • Famine • Gurdy Jr. • The Blighted Ovum|
|The Caves||Fistula • Peep • Gurdy • Chub • C.H.A.D. • Pestilence|
|Catacombs||The Husk • The Hollow • The Blighted Ovum • The Carrion Queen • Peep • Pestilence • The Wretched • Gurdy Jr.|
|The Depths||Loki • Monstro II • Gish • War • Mom|
|Necropolis||Mask of Infamy • Daddy Long Legs • The Carrion Queen • The Bloat • Loki • War • The Wretched • Mom|
|The Womb||Scolex • Blastocyst • The Bloat • Death • Conquest • Daddy Long Legs • Triachnid • Teratoma • Mom's Heart • It Lives|
|Utero||Teratoma • The Bloat • Death • Conquest • Daddy Long Legs • Triachnid • Lokii • Mom's Heart • It Lives|
|Sheol||The Fallen • Satan|
|First to fifth and seventh level||The Fallen • Headless Horseman|