Cute tiny guy making a home out of sand!!

[ISpeakForTheSeas]

Thanks! Do you know the macroalgaes name?

Red Grape algae - Botryocladia sp.

I’m not an expert, but it looks to me like it may also be “Red Grape Algae” (to my understanding, both red bubble algae and red grape algae are Botryocladia spp.) - red grape is typically considered positive, red bubble is not. My understanding is that if the bubble is growing on a stalk (if it has a stem), then it’s red grape; if there’s no stalk/stem (just a bubble not raised off the surface of whatever it’s growing on), then it’s red bubble.

 

[Stomatopods17]

Looks like a pistol shrimp imo. Could be any shrimp really.

Really hard to make out but I don't see any mantis defining features.

 

[Hadla]

If we are looking at that candy cane striped literal shrimp, then yeah I don’t think it’s a mantis either lol