The Monstrous Roc spawns in a square room. There is a ledge around the outside edge of the room, the inside is filled with honey. Pull the Roc out of the honey and pull him around the ledge.
The Roc will lay exploding eggs during the fight - the game emotes in red when he lays one. The eggs will explode after 5-7 seconds, doing about 100K damage if you're caught in the explosion. The eggs can be prematurely detonated if you're careless with AOEs.
The Monstrous Roc also has a joustable AOE called "Squawk!". In Advanced Solo, Squawk! only seems to stun you, but being stunned can trap you in the eggsplosion radius.