On the Butt of Lewis we encountered a Grey Seal, he came up for air every few minutes.
I first spotted this weird triangle, really had to look whether it was a rock or something else but when it disappeared I knew I had to pay attention 

This is him when I spotted him a second time
 Canon 100-400 IS MkII on Sony a7RII
Canon 100-400 IS MkII on Sony a7RIILater in the evening he came in for a look 

 Canon 100-400 IS MkII on Sony a7RII
Canon 100-400 IS MkII on Sony a7RII