It walks at its speed the way it faces, warbling if it walks into a wall while on the screen (BUMP_SOUND), turning when it is stopped and every so often -- a monster with bit 5 of its flags set turns towards the knight (STEER) -- and takes its frame from its facing (FACING_PICTURE). Three cells or more from the knight it is forgotten: its record is emptied. Touching him it scores 2500 and takes one of his hits, bursting (WANDERING_MONSTER).

Struck by an antibody (ANTIBODY_STRIKE), its fate depends on the two kinds together: a monster's kind is bits 2-3 of its graphic (112, 116, 120 or 124 on), an antibody's the same bits of its (80, 84, 88 or 92 on), and their sum, four apart, picks a routine from MONSTER_HIT_TABLE: destroyed, changed into the next kind, split in two, or turned into a monster of 64-79. A monster's kind is that of the villain nearest where it appeared (APPEARING_UPDATE), so each villain's monsters are destroyed by one kind of antibody.