( ( ( ( -LCB- ( U -RCB- ) ) : ) ( Regenerate ( ( ~ ( ( this ( ~ . ) ) ( Play ( this ability ) ) ) ) ( only ( if ( ( ~ ( this ~ ) ) ( ( ( blocked or ) ( was ( blocked ( by ( a ( blue creature ) ) ) ) ) ) ( this turn ) ) ) ) ) ) ) ) . )
(ROOT (NP (NP (-LRB- -LCB-) (NNP U) (-RRB- -RCB-)) (: :) (NP (NP (NNP Regenerate)) (VP (VBG ~) (S (NP (DT this) (NNP ~) (. .)) (VP (NNP Play) (NP (DT this) (NN ability)))) (SBAR (RB only) (IN if) (S (NP (JJ ~) (DT this) (NN ~)) (VP (VP (VBD blocked)) (CC or) (VP (VBD was) (VP (VBN blocked) (PP (IN by) (NP (DT a) (JJ blue) (NN creature))))) (NP (DT this) (NN turn))))))) (. .)))
{U}: Regenerate ~this~. Play this ability only if ~this~ blocked or was blocked by a blue creature this turn.
(ROOT (S (NP (DT A) (JJ blue) (NN block)) (VP (VBZ appears) (ADJP (JJ blue) (PP (IN in) (NP (DT the) (NN sunlight)))) (SBAR (IN if) (S (NP (RB only) (JJ blue) (NN light)) (VP (VBZ is) (VP (VBN reflected) (PP (IN by) (NP (DT the) (NN block)))))))) (. .)))