Okay, I've taken a stab at verses one and two . . . have at the rest!
You're a mean one, Mr. Grinch
You really are all wet
You're as snowy as the tropics, with your subtropical jet, Mr. Grinch
You're a roaring sou'easter and you're making us fret!
You're a monster, Mr. Grinch
Our ground is bare and brown
Your rain will leave us flooded, and our sorrows we must drown, Mr. Grinch
But Kev will still be happy if all his trees come tumbling down!
[Verse 3]
You're a vile one, Mr. Grinch
You have termites in your smile
You have all the tender sweetness of a seasick crocodile, Mr. Grinch
Given a choice between the two of you I'd take the seasick crocodile!
[Verse 4]
You're a foul one, Mr. Grinch
You're a nasty-wasty skunk
Your heart is full of unwashed socks, your soul is full of gunk, Mr. Grinch
The three words that best describe you are as follows, and I quote
"Stink, stank, stunk!"
[Verse 5]
You're a rotter, Mr. Grinch
You're the king of sinful sots
Your heart's a dead tomato splotched with moldy purple spots, Mr. Grinch
Your soul is an appalling dump heap overflowing with the most disgraceful
Assortment of deplorable rubbish imaginable, mangled up in tangled up knots!
[Verse 6]
You nauseate me, Mr. Grinch
With a nauseous super "naus"!
You're a crooked dirty jockey and you drive a crooked hoss, Mr. Grinch
You're a three decker sauerkraut and toadstool sandwich with arsenic sauce!