According to this Pokémon's pokédex entry, it likes sunsets, long walks on the beach, and... well, killing you so you can be friends forever.

Wow… No wonder this Pokémon creeper made the Top 10 for Most Terrifying Pokédex Entries!

I'll just leave you a list of the top five most expensive Gengars while I go hide under a blanket…

# 5 Skyridge Gengar

Too bad this isn't the shiny version, or he'd be #1.

# 4 Expedition Gengar (13)

"You've got damage? Now they've got the damage! I'ma go sit on the bench now."

# 3 Dark Gengar

If you suddenly feel cold, don't drift off to sleep—this Gengar might not let you wake up!

# 2 Gengar ex

A poltergeist?! This house is NOT clean...

#1 Holo Rare Gengar

Heads or tails, this shiny little bugger's gonna make the Defending Pokémon cry.