隠れ家から飛び出す繊毛虫;Jumping from particles

Japanese commentary is followed by English commentary

粒子の間で何やらうごめく不思議な生き物、身体の先端が特にぴくぴく動いています。すると突然、身体を伸び縮みさせ、粒子の陰に姿を隠し、次にすごい勢いで外へ飛び出して­行きました。余りの早さに繊毛虫であることの確認も出来ません。

----- 月井雄二先生(法政大)のコメント -----
コメント通りで，おそらく繊毛虫だろうということ以外はわかりません。

An organism is twitching in a narrow space between particles. After a while it begins to contract and expand its body, hides itself behind the particles, then suddenly jumps out and shoots out of our view. The organism is gone in an instant so it is difficult to determine if it is a ciliate.

----- Commentary by Prof. Yuji Tsukii, Hosei University -----
As described in the video commentary, this is may be a ciliate, but it is difficult to know for sure.