As an uber Genesis nerd since the 70s, this is a subject that is very big in my world.  Way too many to list, so I'll just drop in a few of my favorites.
 

The Colony Of Slippermen
The Arrival
 
 Rael:
 I wandered lonely as a cloud,
 Till I came upon this dirty street.
 I've never seen a stranger crowd;
 Slubberdegullions on a squeaky feet,
 
 Continually pacing,
 With nonchalant embracing,
 Each orifice disgracing
 And one facing me moves to say "hellay".
 
 His skin's all covered in slimy lumps.
 With lips that slide across each chin.
 His twisted limbs like rubber stamps
 Are waved in welcome say 'Please join in.'
 
 My grip must be flipping,
 Cos his handshake keeps slipping,
 My hopes keep on dipping
 And his lips keep on smiling all the time.
 
 Slipperman:
 "We like you, have tasted love.
 Don't be alarmed at what you see,
 You yourself are just the same
 As what you see in me."
 
 Rael:
 Me, like you? like that!
 
 Slipperman:
 "You better watch it son, your sentence has only just begun
 You better run and join your brother John."
 
 A Visit to the Doktor
 
 Slipperman:
 "You're in the colony of slippermen.
 There's no who? why? what? or when?
 
 You get out if you've got the gripe
 To see, Doktor Dyper, reformed sniper-
 he'll whip off your windscreenwiper
 
 Rael:
 John and I are able
 To face the Doktor and his marble table.
 
 The Doktor:
 Understand Rael, it's the end of your tail.
 
 Rael:
 "Don't delay, dock the dick!"
 I watch his countdown timer tick......
 
 
 The Raven
 
 He places the number into a tube,
 A yellow plastic "shoobedoobe".
 It says: "Though your fingers may tickle
 You'll be safe in our pickle."
 Suddenly, black cloud comes down from the sky.
 It's a supersize black bird that sure can fly.
 
 The raven brings on darkness and night
 He flies right down, gives me one hell of a fright.
 He takes the tube right out of my hands
 Man, I've got to find out where that black bird lands.
 
 "Look here John, I've got to run
 I need you now, you going to come?"
 He says to me.
 
 John:
 "Now can't you see
 Where the raven flies there's jeopardy.
 
 We've been cured on the couch
 Now you're sick with your grouch.
 I'll not risk my honey pouch
 Which my slouch will wear slung very low."
 
 Rael:
 He walks away and leaves me once again.
 Even though I never learn,
 I'd hoped he'd show just some concern.
 
 I'm in agony of Slipperpain
 I pray my undercarriage will sustain.
 The chase is on, the pace is hot
 But I'm running so very hard with everything I've got.
 He leads me down an underpass
 Though it narrows, he still flies very fast,
 When the tunnel stops
 I catch sight of the tube, just as it drops.
 I'm on top of a bank, to steep to climb,
 I see it hit the water, just in time,
 to watch it float away.