Segue a maneira que montei o meu creeper.
<canvas width="600" height="400"></canvas>
<script>
var tela= document.querySelector("canvas");
var pincel= tela.getContext("2d");
//retanguloGeral
/*
pincel.fillStyle= "lightGrey";
pincel.fillRect(0,0,600,400);
*/
// Cabeça
pincel.fillStyle="darkGreen";
pincel.fillRect(125,50, 350,300);
// Naris
pincel.fillStyle="black";
pincel.fillRect(265,200, 70,100);
// Olho 2
pincel.fillStyle="black";
pincel.fillRect(175,110, 90,90);
// Olho 3
pincel.fillStyle="black";
pincel.fillRect(335,110, 90,90);
// Boca 5
pincel.fillStyle="black";
pincel.fillRect(225,240, 40,110);
// Boca 6
pincel.fillStyle="black";
pincel.fillRect(335,240, 40,110);
</script>