1. Carpet anemones are substrate dwelling animals, therefore it wanted to move the the sand bed. I hope its a sand bed anyway.
2. If it looks like melted ice cream than it may very well be dieing. Post a pic if you can. Don't panic yet it may simply be expelling waste. Where exactly is the "slime"
Need more information though.
What size tank?
What exaclty is the lighting, everything about the lights?
Photo period?
How long have you had the anemone?
Check those water paramiters please.
Thomas