Hi all - I need some grammar help for one of my writers and being an old broad have forgotten.   Which is correct?  (Or if none of these, what is?)

Spike lay next to her on the bed. 

Spike laid next to her on the bed.

Spike lied next to her on the bed.

Spike lied down next to her on the bed.

I'm pretty sure it would be "lay," since "laid" usually refers to an object (he laid the pillow on the bed). 

To be more specific ...

"Lie" is present tense. "Lay" is past tense. "Lain" is past participle.

Thanks UB.